diff --git a/README.md b/README.md
index e6ca9946..c636cb13 100644
--- a/README.md
+++ b/README.md
@@ -111,7 +111,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 <p align="center">
   <a href="showcase/shipping-crate/"><img src="showcase/shipping-crate/preview.webp" width="24%" alt="Shipping crate: a wooden slat crate with iron corner brackets on a dark studio floor, warm wedge on the back wall" /></a>
   <a href="showcase/stone-well/"><img src="showcase/stone-well/preview.webp" width="24%" alt="Stone well: a round brick well with a shingled pyramid roof on posts, rope and bucket, on a dark studio floor" /></a>
-  <a href="showcase/wooden-barrel/"><img src="showcase/wooden-barrel/preview.webp" width="24%" alt="Wooden barrel: a 20-stave wine-cask with croze-seated heads, chord-lofted iron hoops, and a bung on a dark studio floor" /></a>
+  <a href="showcase/wooden-barrel/"><img src="showcase/wooden-barrel/preview.webp" width="24%" alt="Wooden barrel: a 20-stave wine-cask with a head of four boards, chord-lofted iron hoops, and a bung on a dark studio floor" /></a>
   <a href="showcase/campfire/"><img src="showcase/campfire/preview.webp" width="24%" alt="Campfire: a two-course stone fire ring with a tripod of logs on a dark studio floor, warm wedge on the back wall" /></a>
   <a href="showcase/market-stall/"><img src="showcase/market-stall/preview.webp" width="24%" alt="Market stall: a timber frame with post feet, slatted counter, rafters, and a striped awning on a dark studio floor, warm wedge on the back wall" /></a>
   <a href="showcase/street-lantern/"><img src="showcase/street-lantern/preview.webp" width="24%" alt="Street lantern: an iron post with brass collars, a braced arm, and a muntined amber cage on a dark studio floor" /></a>
@@ -129,7 +129,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/hand-pump/"><img src="showcase/hand-pump/preview.webp" width="24%" alt="Hand pump: a cast-iron village pump on a wooden plinth with a spout and handle on a dark studio floor" /></a>
   <a href="showcase/signpost/"><img src="showcase/signpost/preview.webp" width="24%" alt="Signpost: a timber post with two painted fingerboards, iron straps, and a pyramidal cap on a dark studio floor" /></a>
   <a href="showcase/chopping-block/"><img src="showcase/chopping-block/preview.webp" width="24%" alt="Chopping block: a bark-sided log round with growth rings and drying checks on its sawn top, a riveted iron hoop, and a felling axe buried in the top, on a dark studio floor" /></a>
-  <a href="showcase/wooden-bucket/"><img src="showcase/wooden-bucket/preview.webp" width="24%" alt="Wooden bucket: a coopered pail with a round rope bail through ear rings and chord-lofted iron hoops on a dark studio floor" /></a>
+  <a href="showcase/wooden-bucket/"><img src="showcase/wooden-bucket/preview.webp" width="24%" alt="Wooden bucket: a coopered pail with a three-strand rope bail through iron ear rings and chord-lofted iron hoops on a dark studio floor" /></a>
   <a href="showcase/wall-torch/"><img src="showcase/wall-torch/preview.webp" width="24%" alt="Wall torch: a dressed stone plaque with an iron sconce, wooden haft, and flame on a dark studio floor" /></a>
   <a href="showcase/tavern-stool/"><img src="showcase/tavern-stool/preview.webp" width="24%" alt="Tavern stool: a round wooden seat on turned splayed legs with stretchers and iron ferrules on a dark studio floor" /></a>
   <a href="showcase/iron-cauldron/"><img src="showcase/iron-cauldron/preview.webp" width="24%" alt="Iron cauldron: a bulged iron pot hanging from a timber tripod on a dark studio floor" /></a>
@@ -143,7 +143,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`stone-well`](showcase/stone-well/) — procedural round stone well, shingled roof, windlass, rope and bucket through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
-[`wooden-barrel`](showcase/wooden-barrel/) — procedural 20-stave wine-cask with croze-seated heads and chord-lofted hoops through the same pipeline. Falsifier `--round-band` exits 18.
+[`wooden-barrel`](showcase/wooden-barrel/) — procedural 20-stave wine-cask with boarded, croze-seated heads and chord-lofted hoops through the same pipeline. Falsifiers `--round-band` exits 18, `--one-piece-head` exits 17.
 
 [`campfire`](showcase/campfire/) — procedural cobble ring, logs, and ash through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
@@ -179,7 +179,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`chopping-block`](showcase/chopping-block/) — procedural hooped timber stump with an embedded axe through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
-[`wooden-bucket`](showcase/wooden-bucket/) — procedural coopered pail with a round bail through the ear rings through the same pipeline. Falsifier `--float-handle` exits 17.
+[`wooden-bucket`](showcase/wooden-bucket/) — procedural coopered pail with a three-strand rope bail through the ear rings through the same pipeline. Falsifiers `--float-handle` and `--sunk-rope` exit 17.
 
 [`wall-torch`](showcase/wall-torch/) — procedural wall-mounted torch sconce with a stone plaque, iron bracket, and flame through the same pipeline. Falsifiers `--skip-decimate` (9), `--stray-vert` (15), `--float-arm` (17).
 
@@ -257,7 +257,7 @@ the compositor on and is exactly zero with it off — and that EEVEE has no `use
 </tr>
 <tr>
 <td width="46%" valign="middle">
-<a href="examples/color-attribute-wheel/"><img src="examples/color-attribute-wheel/preview.webp" alt="Color attribute wheel: an HSV color wheel disc with a white center fading into a vivid rainbow rim, leaning upright toward the camera on a dark studio floor with a warm light pool behind it" /></a>
+<a href="examples/color-attribute-wheel/"><img src="examples/color-attribute-wheel/preview.webp" alt="Color attribute wheel: an HSV color wheel board with a white center fading into a vivid rainbow rim, leaning back on a dark plinth on a dark studio floor with a warm light pool behind it" /></a>
 </td>
 <td valign="middle">
 
@@ -361,7 +361,7 @@ then re-reads its own render and fails unless the pixels prove the flat-vs-check
 </tr>
 <tr>
 <td width="46%" valign="middle">
-<a href="examples/wave-displace/"><img src="examples/wave-displace/preview.webp" alt="Wave displace: a glossy sapphire-blue surface displaced into smooth standing-wave dunes against a black backdrop" /></a>
+<a href="examples/wave-displace/"><img src="examples/wave-displace/preview.webp" alt="Wave displace: a sapphire-blue tile whose top is displaced into smooth standing-wave dunes, standing on a dark studio floor" /></a>
 </td>
 <td valign="middle">
 
diff --git a/docs/gallery/assets/color-attribute-wheel-hero.webp b/docs/gallery/assets/color-attribute-wheel-hero.webp
index e8867fbf..be0d0732 100644
Binary files a/docs/gallery/assets/color-attribute-wheel-hero.webp and b/docs/gallery/assets/color-attribute-wheel-hero.webp differ
diff --git a/docs/gallery/assets/wave-displace-hero.webp b/docs/gallery/assets/wave-displace-hero.webp
index a15156a1..99250a4f 100644
Binary files a/docs/gallery/assets/wave-displace-hero.webp and b/docs/gallery/assets/wave-displace-hero.webp differ
diff --git a/docs/gallery/assets/wooden-barrel-hero.webp b/docs/gallery/assets/wooden-barrel-hero.webp
index 93a87ede..12d00207 100644
Binary files a/docs/gallery/assets/wooden-barrel-hero.webp and b/docs/gallery/assets/wooden-barrel-hero.webp differ
diff --git a/docs/gallery/assets/wooden-bucket-hero.webp b/docs/gallery/assets/wooden-bucket-hero.webp
index a4c5d2c7..78f02403 100644
Binary files a/docs/gallery/assets/wooden-bucket-hero.webp and b/docs/gallery/assets/wooden-bucket-hero.webp differ
diff --git a/docs/gallery/color-attribute-wheel/index.html b/docs/gallery/color-attribute-wheel/index.html
index e529d629..edd38600 100644
--- a/docs/gallery/color-attribute-wheel/index.html
+++ b/docs/gallery/color-attribute-wheel/index.html
@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/color-attribute-wheel-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A disc painted with a full hue wheel that fades to white at the centre." />
+  <meta property="og:image:alt" content="A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="color-attribute-wheel — Examples — Blender Developer Tools" />
   <meta name="twitter:description" content="The modern color-attributes API — mesh.color_attributes.new() on the CORNER domain, filled by expanding per-vertex HSV across face corners with foreach_get/foreach_set, then wired into a shader Attribute node." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/color-attribute-wheel-hero.webp" />
-  <meta name="twitter:image:alt" content="A disc painted with a full hue wheel that fades to white at the centre." />
+  <meta name="twitter:image:alt" content="A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth." />
   <style>
     /* fonts are deployed by the landing build (docs/fonts/) */
     @font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
@@ -268,8 +268,8 @@ <h1>color-attribute-wheel</h1>
     <p>The modern color-attributes API — mesh.color_attributes.new() on the CORNER domain, filled by expanding per-vertex HSV across face corners with foreach_get/foreach_set, then wired into a shader Attribute node.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A disc painted with a full hue wheel that fades to white at the centre.">
-      <img src="../assets/color-attribute-wheel-hero.webp" alt="A disc painted with a full hue wheel that fades to white at the centre." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth.">
+      <img src="../assets/color-attribute-wheel-hero.webp" alt="A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth." width="1280" height="720" />
     </button>
     <p class="zoom-hint">Rendered headless by the example itself — click to zoom.</p>
     <div class="callout"><span class="tag">witnesses</span> CORNER-domain attributes are sized to loop count, not vertex count; the check asserts the sizing, that active_color points at it, and that the Attribute node is actually linked to Base Color, not just present.</div>
@@ -280,6 +280,8 @@ <h1>color-attribute-wheel</h1>
     <section class="detail-section md">
 <p>A runnable example that builds an HSV color wheel disc entirely with <code>bmesh</code> and colors it with <code>Mesh.color_attributes.new()</code> — the modern attributes API, not the deprecated <code>Mesh.vertex_colors</code> alias AI code keeps reaching for. It witnesses the domain trap that comes with it: a <code>CORNER</code>-domain attribute is sized to <code>len(mesh.loops)</code>, not <code>len(mesh.vertices)</code>, so per-vertex data has to be expanded across face corners before it is written. The material wires the same attribute into a Shader <code>Attribute</code> node (<code>attribute_type=&#x27;GEOMETRY&#x27;</code>) feeding Base Color — the step AI code most often skips, leaving the mesh gray even when the attribute data is correct.</p>
 <p><strong>What it witnesses:</strong> a <code>FLOAT_COLOR</code> attribute on the <code>CORNER</code> domain, filled with one <code>foreach_get</code> (loop → vertex index) and one <code>foreach_set</code> (loop color), never a per-loop Python assignment. The check asserts the attribute is sized to the loop count and <em>not</em> the vertex count, that it is <code>color_attributes.active_color</code> (so a renderer or exporter actually picks it up), and that several probe loops match the closed-form HSV value for the vertex they reference. A separate check in the render path confirms the <code>Attribute</code> node is actually linked to Base Color, not just present in the node tree.</p>
+<h2>Staging</h2>
+<p>The disc is zero-thickness, and the still used to show it as a paper-thin oval hovering 8 cm above the floor. The render path now gives it a render-only Solidify body (5 cm) and stands it at the same 52° lean on a dark plinth, with a strut behind it, easel-style. The height is computed so the lowest point of the rim rests on the plinth. The mesh <code>check()</code> asserts is unchanged: the modifier is added after the check and only in the render path. Measured framing on 5.2.1: fill 0.794 y, every margin ≥ 0.094.</p>
 <h2>Run</h2>
 <pre><code># Cheap correctness check (no render) — the CI check:
 blender --background --python color_attribute_wheel.py --
@@ -326,6 +328,7 @@ <h2>Source</h2>
 &quot;&quot;&quot;</span>
 <span class="k">import</span> bpy, bmesh, sys, os, math, colorsys, argparse
 <span class="k">from</span> array <span class="k">import</span> array
+<span class="k">from</span> mathutils <span class="k">import</span> Vector
 
 RINGS = <span class="n">14</span>
 SEGMENTS = <span class="n">72</span>
@@ -500,8 +503,54 @@ <h2>Source</h2>
     <span class="c"># stand the disc up toward the camera like an easel: the wheel is the</span>
     <span class="c"># subject, so it should present nearly face-on and fill the frame instead</span>
     <span class="c"># of lying foreshortened on the floor.</span>
-    obj.location = (<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.34</span>)
-    obj.rotation_euler = (math.radians(<span class="n">52</span>), <span class="n">0.0</span>, math.radians(<span class="n">10</span>))
+    <span class="c"># render-only: a Solidify body so the disc reads as a painted board, not</span>
+    <span class="c"># a zero-thickness sheet, resting on a dark plinth and propped from</span>
+    <span class="c"># behind by a strut, easel-style, instead of hovering above the floor.</span>
+    disc_t = <span class="n">0.05</span>
+    plinth_h = <span class="n">0.12</span>
+    tilt = math.radians(<span class="n">52</span>)
+    solid = obj.modifiers.new(<span class="s">&quot;Board&quot;</span>, <span class="s">&#x27;SOLIDIFY&#x27;</span>)
+    solid.thickness = disc_t
+    solid.offset = -<span class="n">1.0</span>
+    <span class="c"># lowest rim point sits R_OUTER * sin(tilt) below the centre, and the</span>
+    <span class="c"># board&#x27;s back face another disc_t * cos(tilt) below that</span>
+    obj.location = (<span class="n">0.0</span>, <span class="n">0.0</span>, plinth_h + R_OUTER * math.sin(tilt) + disc_t * math.cos(tilt))
+    obj.rotation_euler = (tilt, <span class="n">0.0</span>, math.radians(<span class="n">10</span>))
+
+    stand_mat = bpy.data.materials.new(<span class="s">&quot;Stand&quot;</span>)
+    stand_mat.use_nodes = <span class="k">True</span>
+    sb = stand_mat.node_tree.nodes[<span class="s">&quot;Principled BSDF&quot;</span>]
+    sb.inputs[<span class="s">&quot;Base Color&quot;</span>].default_value = (<span class="n">0.012</span>, <span class="n">0.012</span>, <span class="n">0.014</span>, <span class="n">1.0</span>)
+    sb.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.45</span>
+
+    <span class="k">def</span> stand_part(name, build):
+        me = bpy.data.meshes.new(name)
+        bm = bmesh.new()
+        <span class="k">try</span>:
+            build(bm)
+            bm.to_mesh(me)
+        <span class="k">finally</span>:
+            bm.free()
+        me.materials.append(stand_mat)
+        ob = bpy.data.objects.new(name, me)
+        scene.collection.objects.link(ob)
+        <span class="k">return</span> ob
+
+    bpy.context.view_layer.update()
+    mw = obj.matrix_world
+    rim_low = mw @ Vector((<span class="n">0.0</span>, -R_OUTER, <span class="n">0.0</span>))
+    plinth = stand_part(<span class="s">&quot;Plinth&quot;</span>, <span class="k">lambda</span> bm: bmesh.ops.create_cube(bm, size=<span class="n">1.0</span>))
+    plinth.scale = (<span class="n">1.5</span>, <span class="n">0.9</span>, plinth_h)
+    plinth.location = (rim_low.x, rim_low.y + <span class="n">0.25</span>, plinth_h / <span class="n">2.0</span>)
+    plinth.rotation_euler = (<span class="n">0.0</span>, <span class="n">0.0</span>, math.radians(<span class="n">10</span>))
+    <span class="c"># the strut runs from the board&#x27;s back, above centre, down to the plinth</span>
+    top = mw @ Vector((<span class="n">0.0</span>, <span class="n">0.45</span>, -disc_t))
+    foot = Vector((top.x, top.y + <span class="n">0.95</span>, plinth_h))
+    span = top - foot
+    strut = stand_part(<span class="s">&quot;Strut&quot;</span>, <span class="k">lambda</span> bm: bmesh.ops.create_cone(
+        bm, cap_ends=<span class="k">True</span>, segments=<span class="n">16</span>, radius1=<span class="n">0.035</span>, radius2=<span class="n">0.035</span>, depth=span.length))
+    strut.location = (top + foot) / <span class="n">2.0</span>
+    strut.rotation_euler = Vector((<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.0</span>)).rotation_difference(span).to_euler()
 
     floor_me = bpy.data.meshes.new(<span class="s">&quot;Floor&quot;</span>)
     bm = bmesh.new()
@@ -550,13 +599,13 @@ <h2>Source</h2>
     light(<span class="s">&quot;Wedge&quot;</span>, (<span class="n">2.0</span>, <span class="n">5.2</span>, <span class="n">3.6</span>), <span class="n">220.0</span>, <span class="n">6.0</span>, (<span class="n">1.0</span>, <span class="n">0.76</span>, <span class="n">0.5</span>), (-<span class="n">68</span>, <span class="n">0</span>, <span class="n">190</span>))
 
     aim = bpy.data.objects.new(<span class="s">&quot;Aim&quot;</span>, <span class="k">None</span>)
-    aim.location = obj.location
+    aim.location = obj.location - Vector((<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">0.2</span>))
     scene.collection.objects.link(aim)
 
     cam_data = bpy.data.cameras.new(<span class="s">&quot;Cam&quot;</span>)
     cam_data.lens = <span class="n">50.0</span>
     cam = bpy.data.objects.new(<span class="s">&quot;Cam&quot;</span>, cam_data)
-    cam.location = (<span class="n">0.0</span>, -<span class="n">8.0</span>, <span class="n">2.4</span>)
+    cam.location = (<span class="n">0.0</span>, -<span class="n">9.4</span>, <span class="n">2.5</span>)
     con = cam.constraints.new(<span class="s">&#x27;TRACK_TO&#x27;</span>)
     con.target = aim
     con.track_axis = <span class="s">&#x27;TRACK_NEGATIVE_Z&#x27;</span>
@@ -618,7 +667,7 @@ <h2>Source</h2>
   </main>
   <dialog class="lightbox" id="lightbox" aria-label="Full-size render">
     <button class="lightbox-close" type="button" autofocus>Close</button>
-    <img src="../assets/color-attribute-wheel-hero.webp" alt="A disc painted with a full hue wheel that fades to white at the centre." />
+    <img src="../assets/color-attribute-wheel-hero.webp" alt="A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/contact-sheets/color-attribute-wheel-contact-sheet.webp b/docs/gallery/contact-sheets/color-attribute-wheel-contact-sheet.webp
new file mode 100644
index 00000000..4b320d43
Binary files /dev/null and b/docs/gallery/contact-sheets/color-attribute-wheel-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/wave-displace-contact-sheet.webp b/docs/gallery/contact-sheets/wave-displace-contact-sheet.webp
index d81131e6..69f7c7a0 100644
Binary files a/docs/gallery/contact-sheets/wave-displace-contact-sheet.webp and b/docs/gallery/contact-sheets/wave-displace-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/wooden-barrel-contact-sheet.webp b/docs/gallery/contact-sheets/wooden-barrel-contact-sheet.webp
index 92f6964c..d7e25dac 100644
Binary files a/docs/gallery/contact-sheets/wooden-barrel-contact-sheet.webp and b/docs/gallery/contact-sheets/wooden-barrel-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/wooden-bucket-contact-sheet.webp b/docs/gallery/contact-sheets/wooden-bucket-contact-sheet.webp
index 2e9b519f..3586d9bc 100644
Binary files a/docs/gallery/contact-sheets/wooden-bucket-contact-sheet.webp and b/docs/gallery/contact-sheets/wooden-bucket-contact-sheet.webp differ
diff --git a/docs/gallery/index.html b/docs/gallery/index.html
index a70fac4c..c4c81e67 100644
--- a/docs/gallery/index.html
+++ b/docs/gallery/index.html
@@ -387,7 +387,7 @@ <h2><a href="depsgraph-export/">depsgraph-export</a></h2>
       </article>
       <article class="card" data-tags="mesh performance">
         <a class="card-media" href="wave-displace/" tabindex="-1" aria-hidden="true">
-          <img src="assets/wave-displace-hero.webp" alt="A blue grid surface displaced into rolling sine-wave hills." loading="lazy" decoding="async" />
+          <img src="assets/wave-displace-hero.webp" alt="A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="wave-displace/">wave-displace</a></h2>
@@ -508,7 +508,7 @@ <h2><a href="damped-track-aim/">damped-track-aim</a></h2>
       </article>
       <article class="card" data-tags="mesh materials attributes">
         <a class="card-media" href="color-attribute-wheel/" tabindex="-1" aria-hidden="true">
-          <img src="assets/color-attribute-wheel-hero.webp" alt="A disc painted with a full hue wheel that fades to white at the centre." loading="lazy" decoding="async" />
+          <img src="assets/color-attribute-wheel-hero.webp" alt="A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="color-attribute-wheel/">color-attribute-wheel</a></h2>
@@ -926,12 +926,12 @@ <h2><a href="stone-well/">stone-well</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="wooden-barrel/" tabindex="-1" aria-hidden="true">
-          <img src="assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by three metal hoops." loading="lazy" decoding="async" />
+          <img src="assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by four iron hoops, its head made of boards." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="wooden-barrel/">wooden-barrel</a></h2>
-          <p class="teaches">A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
-          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 7216 tris, two materials with 2512 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget.</p>
+          <p class="teaches">A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 7312 tris, two materials with 2584 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, four boards per head with 1.5 mm seams, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget; --one-piece-head exits 17 on the head-board budget.</p>
           <a class="card-link" href="wooden-barrel/">View showcase piece<span class="sr-only"> wooden-barrel</span> <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
@@ -1124,12 +1124,12 @@ <h2><a href="chopping-block/">chopping-block</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="wooden-bucket/" tabindex="-1" aria-hidden="true">
-          <img src="assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with metal hoops and a curved wooden bail handle." loading="lazy" decoding="async" />
+          <img src="assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="wooden-bucket/">wooden-bucket</a></h2>
-          <p class="teaches">A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
-          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 4872 tris, three materials with 1424 wood, 1020 metal, and 208 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.383×0.346×0.527 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0013 m, LOD ratios in band, convex collider 302 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget.</p>
+          <p class="teaches">A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 5458 tris, three materials with 1448 wood, 1020 metal, and 486 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.396×0.346×0.534 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0011 m, three bottom boards, no rope vertex inside an ear plate, LOD ratios in band, convex collider 276 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget; --sunk-rope exits 17 on the rope-clearance budget.</p>
           <a class="card-link" href="wooden-bucket/">View showcase piece<span class="sr-only"> wooden-bucket</span> <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
diff --git a/docs/gallery/wave-displace/index.html b/docs/gallery/wave-displace/index.html
index f00a565e..cbbabcea 100644
--- a/docs/gallery/wave-displace/index.html
+++ b/docs/gallery/wave-displace/index.html
@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/wave-displace-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A blue grid surface displaced into rolling sine-wave hills." />
+  <meta property="og:image:alt" content="A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="wave-displace — Examples — Blender Developer Tools" />
   <meta name="twitter:description" content="Bulk vertex IO at real scale — 9,409 vertices displaced into a standing wave with one foreach_get and one foreach_set, no per-vertex access." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/wave-displace-hero.webp" />
-  <meta name="twitter:image:alt" content="A blue grid surface displaced into rolling sine-wave hills." />
+  <meta name="twitter:image:alt" content="A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor." />
   <style>
     /* fonts are deployed by the landing build (docs/fonts/) */
     @font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
@@ -268,8 +268,8 @@ <h1>wave-displace</h1>
     <p>Bulk vertex IO at real scale — 9,409 vertices displaced into a standing wave with one foreach_get and one foreach_set, no per-vertex access.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A blue grid surface displaced into rolling sine-wave hills.">
-      <img src="../assets/wave-displace-hero.webp" alt="A blue grid surface displaced into rolling sine-wave hills." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor.">
+      <img src="../assets/wave-displace-hero.webp" alt="A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor." width="1280" height="720" />
     </button>
     <p class="zoom-hint">Rendered headless by the example itself — click to zoom.</p>
     <div class="callout"><span class="tag">witnesses</span> The bulk path is correct, not just fast: the Z span matches the wave amplitude and every vertex matches the closed-form wave, so a stride bug in the flat buffer cannot hide.</div>
@@ -280,8 +280,9 @@ <h1>wave-displace</h1>
     <section class="detail-section md">
 <p>A runnable example that displaces a 96×96 grid (9,409 vertices) into a standing wave using <strong>one <code>foreach_get</code> and one <code>foreach_set</code></strong> — the bulk-IO pattern from <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/rules/use-foreach-set-for-bulk-data.mdc"><code>use-foreach-set-for-bulk-data</code></a> and the <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/skills/mesh-editing-and-bmesh/SKILL.md"><code>mesh-editing-and-bmesh</code></a> skill — instead of 9,409 individual <code>mesh.vertices[i].co</code> accesses.</p>
 <p><strong>What it witnesses:</strong> the bulk path is not just faster, it is <em>correct</em> — the check asserts the flat grid gained the expected Z span (the write actually landed) and that <strong>every</strong> vertex matches the closed-form wave, so a stride or interleave bug in the flat buffer cannot hide behind a lucky probe.</p>
-<h2>Framing deviation</h2>
-<p>Edge-to-edge field — the displaced sheet fills the frame and crops at the left, right, and bottom edges so the wave reads as a surface, not an object on a stage (measured fill 1.000x/0.817y with edge touch on three sides). If wired to <code>examples/gallery_framing.py</code>, call it with <code>deviation=&quot;edge-to-edge wave field; the fill is the point&quot;</code>.</p>
+<h2>Staging</h2>
+<p>The still used to be an edge-to-edge field: the sheet cropped at the left, right and bottom edges on a black void, so nothing showed where the surface ended or what it stood on. <code>gallery_framing</code> has no <code>deviation=</code> flag any more, so that framing could not be gated at all.</p>
+<p>The render path now stages a <strong>copy</strong> of the checked grid. Its boundary is extruded straight down to a flat base 0.30 m below the deepest trough, so the wave is the top face of a cast tile standing on the studio floor, framed whole. The checked <code>Wave</code> object is left exactly as asserted and hidden from the render. The copy is render-only and never enters <code>check()</code>. Measured framing on 5.2.1: fill 0.753 x / 0.761 y, every margin ≥ 0.117.</p>
 <h2>Run</h2>
 <pre><code># Cheap correctness check (no render) — the CI check:
 blender --background --python wave_displace.py --
@@ -391,31 +392,87 @@ <h2>Source</h2>
     bsdf.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.18</span>
     obj.data.materials.append(mat)
 
+    <span class="c"># render-only staging: the displaced grid is the contract and stays as</span>
+    <span class="c"># checked. A copy of it gets a skirt, its boundary extruded straight</span>
+    <span class="c"># down to a flat base, so the wave reads as the top of a cast tile</span>
+    <span class="c"># standing on the studio floor instead of a sheet bleeding off the frame.</span>
+    base = <span class="n">0.30</span>  <span class="c"># base sits this far below the deepest trough</span>
+    tile_me = obj.data.copy()
+    bm = bmesh.new()
+    <span class="k">try</span>:
+        bm.from_mesh(tile_me)
+        rim = [e <span class="k">for</span> e <span class="k">in</span> bm.edges <span class="k">if</span> e.is_boundary]
+        ret = bmesh.ops.extrude_edge_only(bm, edges=rim)
+        skirt = [g <span class="k">for</span> g <span class="k">in</span> ret[<span class="s">&quot;geom&quot;</span>] <span class="k">if</span> isinstance(g, bmesh.types.BMFace)]
+        <span class="k">for</span> g <span class="k">in</span> ret[<span class="s">&quot;geom&quot;</span>]:
+            <span class="k">if</span> isinstance(g, bmesh.types.BMVert):
+                g.co.z = -AMP - base
+        bottom = [g <span class="k">for</span> g <span class="k">in</span> ret[<span class="s">&quot;geom&quot;</span>] <span class="k">if</span> isinstance(g, bmesh.types.BMEdge) <span class="k">and</span> g.is_boundary]
+        bmesh.ops.holes_fill(bm, edges=bottom, sides=<span class="n">0</span>)
+        bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
+        <span class="k">for</span> f <span class="k">in</span> skirt:
+            f.smooth = <span class="k">False</span>
+        bm.to_mesh(tile_me)
+    <span class="k">finally</span>:
+        bm.free()
+    tile = bpy.data.objects.new(<span class="s">&quot;WaveTile&quot;</span>, tile_me)
+    tile.location.z = AMP + base
+    scene.collection.objects.link(tile)
+    obj.hide_render = <span class="k">True</span>
+
+    floor_me = bpy.data.meshes.new(<span class="s">&quot;Floor&quot;</span>)
+    bm = bmesh.new()
+    <span class="k">try</span>:
+        bmesh.ops.create_grid(bm, x_segments=<span class="n">1</span>, y_segments=<span class="n">1</span>, size=<span class="n">60.0</span>)
+        bm.to_mesh(floor_me)
+    <span class="k">finally</span>:
+        bm.free()
+    fmat = bpy.data.materials.new(<span class="s">&quot;Studio&quot;</span>)
+    fmat.use_nodes = <span class="k">True</span>
+    fb = fmat.node_tree.nodes[<span class="s">&quot;Principled BSDF&quot;</span>]
+    fb.inputs[<span class="s">&quot;Base Color&quot;</span>].default_value = (<span class="n">0.03</span>, <span class="n">0.032</span>, <span class="n">0.037</span>, <span class="n">1.0</span>)
+    fb.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.7</span>
+    floor_me.materials.append(fmat)
+    floor = bpy.data.objects.new(<span class="s">&quot;Floor&quot;</span>, floor_me)
+    scene.collection.objects.link(floor)
+    wall = bpy.data.objects.new(<span class="s">&quot;Wall&quot;</span>, floor_me.copy())
+    wall.location = (<span class="n">0.0</span>, <span class="n">14.0</span>, <span class="n">0.0</span>)
+    wall.rotation_euler = (math.radians(<span class="n">90</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
+    scene.collection.objects.link(wall)
+
     world = bpy.data.worlds.new(<span class="s">&quot;World&quot;</span>)
     world.use_nodes = <span class="k">True</span>
-    world.node_tree.nodes[<span class="s">&quot;Background&quot;</span>].inputs[<span class="s">&quot;Color&quot;</span>].default_value = (<span class="n">0.008</span>, <span class="n">0.009</span>, <span class="n">0.012</span>, <span class="n">1.0</span>)
+    world.node_tree.nodes[<span class="s">&quot;Background&quot;</span>].inputs[<span class="s">&quot;Color&quot;</span>].default_value = (<span class="n">0.02</span>, <span class="n">0.021</span>, <span class="n">0.025</span>, <span class="n">1.0</span>)
     scene.world = world
 
-    <span class="c"># grazing cool key picks out the crests; warm rim from behind</span>
-    key = bpy.data.lights.new(<span class="s">&quot;Key&quot;</span>, <span class="s">&#x27;AREA&#x27;</span>); key.energy = <span class="n">2000.0</span>; key.size = <span class="n">6.0</span>
-    key.color = (<span class="n">0.9</span>, <span class="n">0.95</span>, <span class="n">1.0</span>)
-    key_ob = bpy.data.objects.new(<span class="s">&quot;Key&quot;</span>, key)
-    key_ob.location = (-<span class="n">6.5</span>, -<span class="n">5.0</span>, <span class="n">3.2</span>)
-    key_ob.rotation_euler = (math.radians(<span class="n">65</span>), <span class="n">0.0</span>, math.radians(-<span class="n">50</span>))
-    scene.collection.objects.link(key_ob)
-    rim = bpy.data.lights.new(<span class="s">&quot;Rim&quot;</span>, <span class="s">&#x27;AREA&#x27;</span>); rim.energy = <span class="n">1300.0</span>; rim.size = <span class="n">4.0</span>
-    rim.color = (<span class="n">1.0</span>, <span class="n">0.68</span>, <span class="n">0.38</span>)
-    rim_ob = bpy.data.objects.new(<span class="s">&quot;Rim&quot;</span>, rim)
-    rim_ob.location = (<span class="n">4.5</span>, <span class="n">6.5</span>, <span class="n">2.6</span>)
-    rim_ob.rotation_euler = (math.radians(-<span class="n">68</span>), <span class="n">0.0</span>, math.radians(<span class="n">148</span>))
-    scene.collection.objects.link(rim_ob)
-
+    <span class="k">def</span> light(name, loc, energy, size, col, rot):
+        ld = bpy.data.lights.new(name, <span class="s">&#x27;AREA&#x27;</span>)
+        ld.energy = energy; ld.size = size; ld.color = col
+        ob = bpy.data.objects.new(name, ld)
+        ob.location = loc
+        ob.rotation_euler = tuple(math.radians(a) <span class="k">for</span> a <span class="k">in</span> rot)
+        scene.collection.objects.link(ob)
+
+    <span class="c"># grazing cool key picks out the crests; warm rim from behind; a warm</span>
+    <span class="c"># wedge rakes the back wall like the rest of the gallery stages</span>
+    light(<span class="s">&quot;Key&quot;</span>, (-<span class="n">8.0</span>, -<span class="n">7.0</span>, <span class="n">6.5</span>), <span class="n">2400.0</span>, <span class="n">7.0</span>, (<span class="n">0.9</span>, <span class="n">0.95</span>, <span class="n">1.0</span>), (<span class="n">55</span>, <span class="n">0</span>, -<span class="n">48</span>))
+    light(<span class="s">&quot;Fill&quot;</span>, (<span class="n">9.0</span>, -<span class="n">6.0</span>, <span class="n">3.0</span>), <span class="n">120.0</span>, <span class="n">10.0</span>, (<span class="n">0.78</span>, <span class="n">0.86</span>, <span class="n">1.0</span>), (<span class="n">70</span>, <span class="n">0</span>, <span class="n">55</span>))
+    light(<span class="s">&quot;Rim&quot;</span>, (<span class="n">5.0</span>, <span class="n">7.5</span>, <span class="n">4.0</span>), <span class="n">1800.0</span>, <span class="n">5.0</span>, (<span class="n">1.0</span>, <span class="n">0.68</span>, <span class="n">0.38</span>), (-<span class="n">62</span>, <span class="n">0</span>, <span class="n">148</span>))
+    light(<span class="s">&quot;Wedge&quot;</span>, (<span class="n">4.0</span>, <span class="n">10.5</span>, <span class="n">7.0</span>), <span class="n">1500.0</span>, <span class="n">9.0</span>, (<span class="n">1.0</span>, <span class="n">0.76</span>, <span class="n">0.5</span>), (-<span class="n">65</span>, <span class="n">0</span>, <span class="n">190</span>))
+
+    aim = bpy.data.objects.new(<span class="s">&quot;Aim&quot;</span>, <span class="k">None</span>)
+    aim.location = (<span class="n">0.0</span>, -<span class="n">0.4</span>, <span class="n">0.05</span>)
+    scene.collection.objects.link(aim)
     cam_data = bpy.data.cameras.new(<span class="s">&quot;Cam&quot;</span>); cam_data.lens = <span class="n">50.0</span>
     cam = bpy.data.objects.new(<span class="s">&quot;Cam&quot;</span>, cam_data)
-    cam.location = (<span class="n">0.0</span>, -<span class="n">8.6</span>, <span class="n">4.6</span>)
-    cam.rotation_euler = (math.radians(<span class="n">62</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
+    cam.location = (<span class="n">7.2</span>, -<span class="n">11.8</span>, <span class="n">7.4</span>)
+    con = cam.constraints.new(<span class="s">&#x27;TRACK_TO&#x27;</span>)
+    con.target = aim
+    con.track_axis = <span class="s">&#x27;TRACK_NEGATIVE_Z&#x27;</span>
+    con.up_axis = <span class="s">&#x27;UP_Y&#x27;</span>
     scene.collection.objects.link(cam)
     scene.camera = cam
+    scene.view_settings.view_transform = <span class="s">&#x27;Standard&#x27;</span>
 
     scene.render.engine = <span class="s">&#x27;CYCLES&#x27;</span> <span class="k">if</span> engine == <span class="s">&#x27;cycles&#x27;</span> <span class="k">else</span> eevee_engine_id()
     <span class="k">if</span> engine == <span class="s">&#x27;cycles&#x27;</span>:
@@ -469,7 +526,7 @@ <h2>Source</h2>
   </main>
   <dialog class="lightbox" id="lightbox" aria-label="Full-size render">
     <button class="lightbox-close" type="button" autofocus>Close</button>
-    <img src="../assets/wave-displace-hero.webp" alt="A blue grid surface displaced into rolling sine-wave hills." />
+    <img src="../assets/wave-displace-hero.webp" alt="A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/wooden-barrel/index.html b/docs/gallery/wooden-barrel/index.html
index da0bb0a4..81eadc88 100644
--- a/docs/gallery/wooden-barrel/index.html
+++ b/docs/gallery/wooden-barrel/index.html
@@ -4,25 +4,25 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1" />
   <title>wooden-barrel — Showcase — Blender Developer Tools</title>
-  <meta name="description" content="A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta name="description" content="A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
   <link rel="canonical" href="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/wooden-barrel/" />
   <link rel="icon" href="../../assets/favicon.svg" type="image/svg+xml" />
   <meta name="theme-color" content="#1a1b1e" />
   <meta name="color-scheme" content="dark" />
   <meta property="og:type" content="website" />
   <meta property="og:title" content="wooden-barrel — Showcase — Blender Developer Tools" />
-  <meta property="og:description" content="A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta property="og:description" content="A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
   <meta property="og:url" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/wooden-barrel/" />
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/wooden-barrel-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A wooden stave barrel bound by three metal hoops." />
+  <meta property="og:image:alt" content="A wooden stave barrel bound by four iron hoops, its head made of boards." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="wooden-barrel — Showcase — Blender Developer Tools" />
-  <meta name="twitter:description" content="A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta name="twitter:description" content="A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/wooden-barrel-hero.webp" />
-  <meta name="twitter:image:alt" content="A wooden stave barrel bound by three metal hoops." />
+  <meta name="twitter:image:alt" content="A wooden stave barrel bound by four iron hoops, its head made of boards." />
   <style>
     /* fonts are deployed by the landing build (docs/fonts/) */
     @font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
@@ -265,36 +265,38 @@
   </div>
   <header class="hero">
     <h1>wooden-barrel</h1>
-    <p>A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+    <p>A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A wooden stave barrel bound by three metal hoops.">
-      <img src="../assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by three metal hoops." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A wooden stave barrel bound by four iron hoops, its head made of boards.">
+      <img src="../assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by four iron hoops, its head made of boards." width="1280" height="720" />
     </button>
     <p class="zoom-hint">Rendered headless by the showcase piece itself — click to zoom.</p>
-    <div class="callout"><span class="tag">witnesses</span> Recomputed: 7216 tris, two materials with 2512 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget.</div>
+    <div class="callout"><span class="tag">witnesses</span> Recomputed: 7312 tris, two materials with 2584 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, four boards per head with 1.5 mm seams, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget; --one-piece-head exits 17 on the head-board budget.</div>
     <div class="runline">
       <pre id="runCmd">blender --background --python showcase/wooden-barrel/wooden_barrel.py --</pre>
       <button class="copy-btn" id="copyRun" type="button">Copy</button>
     </div>
     <section class="detail-section md">
-<p>A showcase piece, not an example. Procedural wine-cask (20 staves with seeded width jitter, heads seated in a croze below a chime, iron hoops lofted on the stave faces, a bung) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.</p>
-<p>Hoops evaluate the same <code>host_outer_r</code> chord as the stave flats. <code>--round-band</code> is the falsifier: a circle of <code>radius_at(z)</code> instead of the chord, which is what made the old capped cylinder float off every face. Heads follow the inner stave polygon, not a circle, so they fill the croze instead of leaving triangular slots at every joint.</p>
+<p>A showcase piece, not an example. Procedural wine-cask (20 staves with seeded width jitter, heads of four boards seated in a croze below a chime, iron hoops lofted on the stave faces, a bung) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.</p>
+<p>Hoops evaluate the same <code>host_outer_r</code> chord as the stave flats. <code>--round-band</code> is the falsifier: a circle of <code>radius_at(z)</code> instead of the chord, which is what made the old capped cylinder float off every face. Heads follow the inner stave polygon, not a circle, so they fill the croze instead of leaving triangular slots at every joint. Each head is that outline cut across into four boards with a 1.5 mm seam, so the seat is unchanged and the head no longer reads as a lid.</p>
 <p>It asserts <strong>budget conformance</strong> of the generated result. It does not witness an API contract. &quot;It rendered without error&quot; is not a check.</p>
 <p><strong>Composes</strong> skills <code>mesh-editing-and-bmesh</code>, <code>bake-high-to-low</code>, <code>depsgraph-and-evaluated-data</code>, <code>engine-export-presets</code>, and snippets <code>bake_normal_high_to_low.py</code>, <code>setup_bake_target_image.py</code>, <code>lod_chain.py</code> / <code>decimate_to_budget.py</code>, <code>convex_hull_collider.py</code>, <code>export_preset_unity.py</code> (helpers copied, not imported as a package).</p>
 <h2>Budgets</h2>
 <p>Declared as named constants; every gate <strong>recomputes</strong> from the mesh, materials, UVs, evaluated LOD, collider, or export file.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (4.5.11 / 5.1.2 / 5.2.1)</th></tr></thead><tbody><tr><td>Base triangles</td><td>6000–8500</td><td>7216 / 7216 / 7216</td></tr><tr><td>LOD1 ratio</td><td>0.32–0.62 of base</td><td>0.5000 / 0.5000 / 0.5000</td></tr><tr><td>LOD2 ratio</td><td>0.10–0.35 of base</td><td>0.2198 / 0.2198 / 0.2198</td></tr><tr><td>Materials</td><td>exactly 2 distinct; ≥400 wood, ≥200 metal faces</td><td>2 slots; 2512 / 1440</td></tr><tr><td>UVs</td><td>in <code>0..1</code>, AABB overlap ≤ 1e-5</td><td>in range, overlap 0</td></tr><tr><td>Outer AABB</td><td>(0.722, 0.714, 0.880) m ± 0.015</td><td>(0.7220, 0.7142, 0.8800), zmin 0</td></tr><tr><td>Collider tris</td><td>≤ 400</td><td>238</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>544140 / 544140 / 544124 bytes</td></tr></tbody></table></div>
-<p>Base triangles rose from <strong>4312 to 7216</strong> in the quality pass: 12 identical staves with 5 mm daylight and circular hoops became 20 jittered staves, 8-ring bulge, chord-seated hoops, polygonal croze heads, and a bung.</p>
+<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (4.5.11 / 5.1.2 / 5.2.1)</th></tr></thead><tbody><tr><td>Base triangles</td><td>6000–8500</td><td>7312 / 7312 / 7312</td></tr><tr><td>LOD1 ratio</td><td>0.32–0.62 of base</td><td>0.5000 / 0.5000 / 0.5000</td></tr><tr><td>LOD2 ratio</td><td>0.10–0.35 of base</td><td>0.2199 / 0.2199 / 0.2199</td></tr><tr><td>Materials</td><td>exactly 2 distinct; ≥400 wood, ≥200 metal faces</td><td>2 slots; 2584 / 1440</td></tr><tr><td>UVs</td><td>in <code>0..1</code>, AABB overlap ≤ 1e-5</td><td>in range, overlap 0</td></tr><tr><td>Outer AABB</td><td>(0.722, 0.714, 0.880) m ± 0.015</td><td>(0.7220, 0.7142, 0.8800), zmin 0</td></tr><tr><td>Collider tris</td><td>≤ 400</td><td>238</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>552456 / 552456 / 552440 bytes</td></tr></tbody></table></div>
+<p>Base triangles rose from <strong>4312 to 7216</strong> in the quality pass: 12 identical staves with 5 mm daylight and circular hoops became 20 jittered staves, 8-ring bulge, chord-seated hoops, polygonal croze heads, and a bung. Cutting each head into four boards added 96 more (7312).</p>
 <p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — the gate is a ratio band, not an exact count. Bake pixels are stochastic; the gate is <code>has_data</code> plus operator <code>FINISHED</code>, not byte-identity. Stave-width jitter uses fixed seed 17. Export byte counts differ by 16 B on 5.2.1 (glTF serializer), not a gated axis.</p>
 <h3>Hygiene</h3>
 <p>Recomputed from the generated mesh, not asserted about the script.</p>
 <div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Non-manifold edges</td><td>0</td><td>0</td></tr><tr><td>Loose verts / edges</td><td>0 / 0</td><td>0 / 0</td></tr><tr><td>Doubles merged at 1e-5</td><td>0</td><td>0</td></tr><tr><td>Zero-area faces</td><td>0</td><td>0</td></tr><tr><td>N-gons</td><td>0</td><td>0</td></tr><tr><td>Coplanar disjoint face pairs</td><td>0</td><td>0</td></tr><tr><td>Grounded: <code>zmin</code></td><td>within 1e-4 of 0</td><td>0.0000</td></tr><tr><td>Named supports: 20 staves</td><td>each <code>zmin</code> ≤ 0.001</td><td>20, stave_z 0.00000</td></tr><tr><td>Body plan</td><td>0.714 m dia × 0.880 m high ± 0.04</td><td>0.7142 × 0.8800</td></tr></tbody></table></div>
 <h3>Joint fit and seat</h3>
-<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Head-croze rim BVH gap</td><td>≤ 0.010 m</td><td>0.00698</td></tr><tr><td>Hoop bite (host r − inner hoop r)</td><td>0.0012–0.008 m</td><td>0.00300</td></tr></tbody></table></div>
+<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Head-croze rim BVH gap</td><td>≤ 0.010 m</td><td>0.00710</td></tr><tr><td>Head boards</td><td>4 per head; every seam 0.0008–0.003 m</td><td>4 + 4; 0.00150</td></tr><tr><td>Hoop bite (host r − inner hoop r)</td><td>0.0012–0.008 m</td><td>0.00300</td></tr></tbody></table></div>
 <h3>Falsifiers</h3>
-<p>Each violates one named budget. All six were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Flag</th><th scope="col">Budget violated</th><th scope="col">Exit</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td></tr><tr><td><code>--stray-vert</code></td><td>loose vertex count is 0</td><td>15</td></tr><tr><td><code>--lift-z</code></td><td>bounding box <code>zmin</code> is 0</td><td>16</td></tr><tr><td><code>--short-staves</code></td><td>named stave supports at Z=0</td><td>16</td></tr><tr><td><code>--float-head</code></td><td>head-croze gap</td><td>17</td></tr><tr><td><code>--round-band</code></td><td>hoop bite band</td><td>18</td></tr></tbody></table></div>
+<p>Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.</p>
+<div class="table-wrap"><table><thead><tr><th scope="col">Flag</th><th scope="col">Budget violated</th><th scope="col">Exit</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td></tr><tr><td><code>--stray-vert</code></td><td>loose vertex count is 0</td><td>15</td></tr><tr><td><code>--lift-z</code></td><td>bounding box <code>zmin</code> is 0</td><td>16</td></tr><tr><td><code>--short-staves</code></td><td>named stave supports at Z=0</td><td>16</td></tr><tr><td><code>--float-head</code></td><td>head-croze gap</td><td>17</td></tr><tr><td><code>--round-band</code></td><td>hoop bite band</td><td>18</td></tr><tr><td><code>--one-piece-head</code></td><td>head boards: 4 per head</td><td>17</td></tr></tbody></table></div>
+<h2>Surface</h2>
+<p>The staves were one flat tone and the hoops bright polished steel. Each stave and each head board now carries a seeded <code>PlankTone</code> and a <code>GrainDir</code> (its own long axis) as face attributes. <code>wood_material</code> stretches grain along that axis, so it runs up the curved staves and across the head boards. The hoops are dark rusted iron, the same recipe as <code>shipping-crate</code>. The temp <code>.glb</code> is removed once its size is measured.</p>
 <h2>Run</h2>
 <pre><code>blender --background --python wooden_barrel.py --
 blender --background --python wooden_barrel.py -- --skip-decimate
@@ -303,11 +305,12 @@ <h2>Run</h2>
 blender --background --python wooden_barrel.py -- --short-staves
 blender --background --python wooden_barrel.py -- --float-head
 blender --background --python wooden_barrel.py -- --round-band
+blender --background --python wooden_barrel.py -- --one-piece-head
 blender --background --python wooden_barrel.py -- --output barrel.png</code></pre>
 <p>Smoke passes no flags.</p>
 <h2>Exit codes</h2>
 <p>File-local. <code>9</code> is a valid check code. <code>10</code> is reserved for <code>gallery_framing.check_framing</code> on the <code>--output</code> path. <code>15</code>–<code>19</code> are the hygiene and joint-fit family.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Code</th><th scope="col">Meaning</th></tr></thead><tbody><tr><td>0</td><td>Success</td></tr><tr><td>1</td><td>Uncaught exception (FATAL wrapper)</td></tr><tr><td>2</td><td>argparse / usage</td></tr><tr><td>3</td><td>Mesh did not build / no UV layer</td></tr><tr><td>4</td><td>Base triangle count outside range</td></tr><tr><td>5</td><td>Material count ≠ 2 distinct slots, or a face-count floor missed</td></tr><tr><td>6</td><td>UVs outside 0..1</td></tr><tr><td>7</td><td>UV AABB overlap above tolerance</td></tr><tr><td>8</td><td>World AABB off declared outer size</td></tr><tr><td>9</td><td>LOD ratio band (<code>--skip-decimate</code> lands here)</td></tr><tr><td>10</td><td>Framing gate (render path only)</td></tr><tr><td>11</td><td>Collider triangle count above ceiling</td></tr><tr><td>12</td><td>Bake did not finish or image has no data</td></tr><tr><td>13</td><td>Export file missing or empty</td></tr><tr><td>14</td><td><code>--output</code> produced no file</td></tr><tr><td>15</td><td>Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight</td></tr><tr><td>16</td><td>Not grounded: bounding box <code>zmin</code> off 0, or a named stave floats</td></tr><tr><td>17</td><td>Joint fit: head-croze gap (<code>--float-head</code>)</td></tr><tr><td>18</td><td>Seat: hoop bite band (<code>--round-band</code>)</td></tr><tr><td>19</td><td>Body diameter or height off the stated real-world size</td></tr></tbody></table></div>
+<div class="table-wrap"><table><thead><tr><th scope="col">Code</th><th scope="col">Meaning</th></tr></thead><tbody><tr><td>0</td><td>Success</td></tr><tr><td>1</td><td>Uncaught exception (FATAL wrapper)</td></tr><tr><td>2</td><td>argparse / usage</td></tr><tr><td>3</td><td>Mesh did not build / no UV layer</td></tr><tr><td>4</td><td>Base triangle count outside range</td></tr><tr><td>5</td><td>Material count ≠ 2 distinct slots, or a face-count floor missed</td></tr><tr><td>6</td><td>UVs outside 0..1</td></tr><tr><td>7</td><td>UV AABB overlap above tolerance</td></tr><tr><td>8</td><td>World AABB off declared outer size</td></tr><tr><td>9</td><td>LOD ratio band (<code>--skip-decimate</code> lands here)</td></tr><tr><td>10</td><td>Framing gate (render path only)</td></tr><tr><td>11</td><td>Collider triangle count above ceiling</td></tr><tr><td>12</td><td>Bake did not finish or image has no data</td></tr><tr><td>13</td><td>Export file missing or empty</td></tr><tr><td>14</td><td><code>--output</code> produced no file</td></tr><tr><td>15</td><td>Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight</td></tr><tr><td>16</td><td>Not grounded: bounding box <code>zmin</code> off 0, or a named stave floats</td></tr><tr><td>17</td><td>Joint fit: head-croze gap (<code>--float-head</code>), or head boards and seams (<code>--one-piece-head</code>)</td></tr><tr><td>18</td><td>Seat: hoop bite band (<code>--round-band</code>)</td></tr><tr><td>19</td><td>Body diameter or height off the stated real-world size</td></tr></tbody></table></div>
     </section>
     <section class="detail-section src">
       <h2>Source</h2>
@@ -330,8 +333,9 @@ <h2>Source</h2>
 They are not API-contract witnesses. Each falsifier violates one named
 budget: ``--skip-decimate`` the LOD-ratio band, ``--stray-vert`` mesh
 hygiene, ``--lift-z`` grounded zmin, ``--short-staves`` named stave
-supports, ``--float-head`` head-croze joint-fit, ``--round-band`` hoop
-seat (hoop generated on a circle instead of the stave chords).
+supports, ``--float-head`` head-croze joint-fit, ``--one-piece-head``
+head boards (one slab instead of boards), ``--round-band`` hoop seat
+(hoop generated on a circle instead of the stave chords).
 
 Fixed seed 17 for stave-width jitter. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
@@ -420,6 +424,19 @@ <h2>Source</h2>
 WOOD_IDX = <span class="n">0</span>
 METAL_IDX = <span class="n">1</span>
 
+<span class="c"># Each head is HEAD_BOARDS boards cut across X from the croze outline, with</span>
+<span class="c"># a BOARD_SEAM between neighbours. A board is a thin wooden shell at least</span>
+<span class="c"># BOARD_MIN_SPAN wide in plan (the bung is 0.05, the narrowest board 0.36).</span>
+HEAD_BOARDS = <span class="n">4</span>
+BOARD_SEAM = <span class="n">0.0015</span>
+BOARD_SEAM_MIN = <span class="n">0.0008</span>
+BOARD_SEAM_MAX = <span class="n">0.003</span>
+BOARD_MIN_SPAN = <span class="n">0.30</span>
+<span class="c"># Per-piece wood tone jitter and grain frequency, as in shipping-crate.</span>
+PLANK_TONE_JITTER = <span class="n">0.28</span>
+TONE_SEED = <span class="n">29</span>
+WOOD_GRAIN_SCALE = <span class="n">30.0</span>
+
 
 <span class="k">def</span> eevee_engine_id():
     <span class="k">return</span> <span class="s">&quot;BLENDER_EEVEE&quot;</span> <span class="k">if</span> bpy.app.version &gt;= (<span class="n">5</span>, <span class="n">0</span>, <span class="n">0</span>) <span class="k">else</span> <span class="s">&quot;BLENDER_EEVEE_NEXT&quot;</span>
@@ -722,6 +739,7 @@ <h2>Source</h2>
     short_staves=<span class="k">False</span>,
     float_head=<span class="k">False</span>,
     round_band=<span class="k">False</span>,
+    one_piece_head=<span class="k">False</span>,
 ):
     bm = bmesh.new()
     gap_ang = GAP_M / R_MID
@@ -734,15 +752,16 @@ <h2>Source</h2>
         bot_z1 = CHIME + LID_T
         top_z0 = HEIGHT - CHIME - LID_T
         top_z1 = HEIGHT - CHIME
-        add_polygon_disk(
+        n_boards = <span class="n">1</span> <span class="k">if</span> one_piece_head <span class="k">else</span> HEAD_BOARDS
+        add_board_disk(
             bm, bot_z0, bot_z1,
             croze_xy(spans, <span class="n">0.5</span> * (bot_z0 + bot_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, n_boards,
         )
-        add_polygon_disk(
+        add_board_disk(
             bm, top_z0, top_z1,
             croze_xy(spans, <span class="n">0.5</span> * (top_z0 + top_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, n_boards,
         )
         add_bung(bm, <span class="n">0.5</span> * (spans[<span class="n">0</span>][<span class="n">0</span>] + spans[<span class="n">0</span>][<span class="n">1</span>]), BUNG_Z, spans)
         build_hoops(bm, spans, round_band)
@@ -980,8 +999,7 @@ <h2>Source</h2>
             <span class="k">continue</span>
         a = shell_aabb(me, g)
         dz = a[<span class="n">5</span>] - a[<span class="n">2</span>]
-        r = <span class="n">0.25</span> * ((a[<span class="n">3</span>] - a[<span class="n">0</span>]) + (a[<span class="n">4</span>] - a[<span class="n">1</span>]))
-        <span class="k">if</span> dz &lt; <span class="n">0.06</span> <span class="k">and</span> r &gt; <span class="n">0.15</span>:
+        <span class="k">if</span> dz &lt; <span class="n">0.06</span> <span class="k">and</span> max(a[<span class="n">3</span>] - a[<span class="n">0</span>], a[<span class="n">4</span>] - a[<span class="n">1</span>]) &gt;= BOARD_MIN_SPAN:
             heads.append(g)
         <span class="k">elif</span> dz &gt; <span class="n">0.50</span>:
             staves.append(g)
@@ -1018,6 +1036,191 @@ <h2>Source</h2>
         bm_s.free()
 
 
+<span class="k">def</span> _long_axis(pts):
+    <span class="s">&quot;&quot;&quot;Principal axis of a point set, by power iteration on its covariance.&quot;&quot;&quot;</span>
+    c = sum(pts, Vector()) / len(pts)
+    cov = [[<span class="n">0.0</span>] * <span class="n">3</span> <span class="k">for</span> _ <span class="k">in</span> range(<span class="n">3</span>)]
+    <span class="k">for</span> p <span class="k">in</span> pts:
+        d = p - c
+        <span class="k">for</span> i <span class="k">in</span> range(<span class="n">3</span>):
+            <span class="k">for</span> j <span class="k">in</span> range(<span class="n">3</span>):
+                cov[i][j] += d[i] * d[j]
+    v = Vector((<span class="n">1.0</span>, <span class="n">0.3</span>, <span class="n">0.1</span>))
+    <span class="k">for</span> _ <span class="k">in</span> range(<span class="n">30</span>):
+        w = Vector([sum(cov[i][j] * v[j] <span class="k">for</span> j <span class="k">in</span> range(<span class="n">3</span>)) <span class="k">for</span> i <span class="k">in</span> range(<span class="n">3</span>)])
+        <span class="k">if</span> w.length &lt; <span class="n">1e-12</span>:
+            <span class="k">break</span>
+        v = w.normalized()
+    <span class="k">return</span> v
+
+
+<span class="k">def</span> paint_planks(me):
+    <span class="s">&quot;&quot;&quot;Per-shell ``PlankTone`` and ``GrainDir`` face attributes for the wood shader.
+
+    Every stave and every board is its own shell, so each gets one tone and
+    grain running along its own long axis (up the curved staves, across
+    the flat boards).
+    &quot;&quot;&quot;</span>
+    tone = [<span class="n">0.5</span>] * len(me.polygons)
+    grain = [(<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.0</span>)] * len(me.polygons)
+    owner = {}
+    rng = random.Random(TONE_SEED)
+    <span class="k">for</span> g <span class="k">in</span> shells(me):
+        pts = [me.vertices[i].co.copy() <span class="k">for</span> i <span class="k">in</span> g]
+        d = _long_axis(pts) <span class="k">if</span> len(pts) &gt; <span class="n">2</span> <span class="k">else</span> Vector((<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.0</span>))
+        t = <span class="n">0.5</span> + rng.uniform(-PLANK_TONE_JITTER, PLANK_TONE_JITTER)
+        <span class="k">for</span> i <span class="k">in</span> g:
+            owner[i] = (t, tuple(d))
+    <span class="k">for</span> poly <span class="k">in</span> me.polygons:
+        t, d = owner[poly.vertices[<span class="n">0</span>]]
+        tone[poly.index] = t
+        grain[poly.index] = d
+    a = me.attributes.new(<span class="s">&quot;PlankTone&quot;</span>, <span class="s">&quot;FLOAT&quot;</span>, <span class="s">&quot;FACE&quot;</span>)
+    a.data.foreach_set(<span class="s">&quot;value&quot;</span>, tone)
+    b = me.attributes.new(<span class="s">&quot;GrainDir&quot;</span>, <span class="s">&quot;FLOAT_VECTOR&quot;</span>, <span class="s">&quot;FACE&quot;</span>)
+    b.data.foreach_set(<span class="s">&quot;vector&quot;</span>, [c <span class="k">for</span> v <span class="k">in</span> grain <span class="k">for</span> c <span class="k">in</span> v])
+
+
+<span class="k">def</span> _sock(sockets, identifier):
+    <span class="s">&quot;&quot;&quot;A Mix-node socket by identifier; its A/B/Result names repeat per type.&quot;&quot;&quot;</span>
+    <span class="k">return</span> next(sk <span class="k">for</span> sk <span class="k">in</span> sockets <span class="k">if</span> sk.identifier == identifier)
+
+
+<span class="k">def</span> wood_material(name):
+    <span class="s">&quot;&quot;&quot;Grain along each stave or board (``GrainDir``), tone per piece (``PlankTone``).&quot;&quot;&quot;</span>
+    mat = bpy.data.materials.new(name)
+    mat.use_nodes = <span class="k">True</span>
+    nt = mat.node_tree
+    bsdf = nt.nodes[<span class="s">&quot;Principled BSDF&quot;</span>]
+    coord = nt.nodes.new(<span class="s">&quot;ShaderNodeTexCoord&quot;</span>)
+    gdir = nt.nodes.new(<span class="s">&quot;ShaderNodeAttribute&quot;</span>)
+    gdir.attribute_name = <span class="s">&quot;GrainDir&quot;</span>
+    tone = nt.nodes.new(<span class="s">&quot;ShaderNodeAttribute&quot;</span>)
+    tone.attribute_name = <span class="s">&quot;PlankTone&quot;</span>
+    dot = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    dot.operation = <span class="s">&quot;DOT_PRODUCT&quot;</span>
+    nt.links.new(coord.outputs[<span class="s">&quot;Object&quot;</span>], dot.inputs[<span class="n">0</span>])
+    nt.links.new(gdir.outputs[<span class="s">&quot;Vector&quot;</span>], dot.inputs[<span class="n">1</span>])
+    squash = nt.nodes.new(<span class="s">&quot;ShaderNodeMath&quot;</span>)
+    squash.operation = <span class="s">&quot;MULTIPLY&quot;</span>
+    squash.inputs[<span class="n">1</span>].default_value = <span class="n">0.94</span>
+    nt.links.new(dot.outputs[<span class="s">&quot;Value&quot;</span>], squash.inputs[<span class="n">0</span>])
+    along = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    along.operation = <span class="s">&quot;SCALE&quot;</span>
+    nt.links.new(gdir.outputs[<span class="s">&quot;Vector&quot;</span>], along.inputs[<span class="n">0</span>])
+    nt.links.new(squash.outputs[<span class="s">&quot;Value&quot;</span>], along.inputs[<span class="s">&quot;Scale&quot;</span>])
+    grain_co = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    grain_co.operation = <span class="s">&quot;SUBTRACT&quot;</span>
+    nt.links.new(coord.outputs[<span class="s">&quot;Object&quot;</span>], grain_co.inputs[<span class="n">0</span>])
+    nt.links.new(along.outputs[<span class="s">&quot;Vector&quot;</span>], grain_co.inputs[<span class="n">1</span>])
+    shift = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    shift.operation = <span class="s">&quot;ADD&quot;</span>
+    nt.links.new(grain_co.outputs[<span class="s">&quot;Vector&quot;</span>], shift.inputs[<span class="n">0</span>])
+    nt.links.new(tone.outputs[<span class="s">&quot;Fac&quot;</span>], shift.inputs[<span class="n">1</span>])
+    noise = nt.nodes.new(<span class="s">&quot;ShaderNodeTexNoise&quot;</span>)
+    noise.inputs[<span class="s">&quot;Scale&quot;</span>].default_value = WOOD_GRAIN_SCALE
+    noise.inputs[<span class="s">&quot;Detail&quot;</span>].default_value = <span class="n">6.0</span>
+    noise.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.62</span>
+    nt.links.new(shift.outputs[<span class="s">&quot;Vector&quot;</span>], noise.inputs[<span class="s">&quot;Vector&quot;</span>])
+    ramp = nt.nodes.new(<span class="s">&quot;ShaderNodeValToRGB&quot;</span>)
+    ramp.color_ramp.elements[<span class="n">0</span>].position = <span class="n">0.30</span>
+    ramp.color_ramp.elements[<span class="n">0</span>].color = (<span class="n">0.12</span>, <span class="n">0.052</span>, <span class="n">0.018</span>, <span class="n">1.0</span>)
+    ramp.color_ramp.elements[<span class="n">1</span>].position = <span class="n">0.72</span>
+    ramp.color_ramp.elements[<span class="n">1</span>].color = (<span class="n">0.38</span>, <span class="n">0.18</span>, <span class="n">0.065</span>, <span class="n">1.0</span>)
+    nt.links.new(noise.outputs[<span class="s">&quot;Fac&quot;</span>], ramp.inputs[<span class="s">&quot;Fac&quot;</span>])
+    gain = nt.nodes.new(<span class="s">&quot;ShaderNodeMath&quot;</span>)
+    gain.operation = <span class="s">&quot;MULTIPLY_ADD&quot;</span>
+    gain.inputs[<span class="n">1</span>].default_value = <span class="n">1.1</span>
+    gain.inputs[<span class="n">2</span>].default_value = <span class="n">0.45</span>
+    nt.links.new(tone.outputs[<span class="s">&quot;Fac&quot;</span>], gain.inputs[<span class="n">0</span>])
+    mix = nt.nodes.new(<span class="s">&quot;ShaderNodeMix&quot;</span>)
+    mix.data_type = <span class="s">&quot;RGBA&quot;</span>
+    mix.blend_type = <span class="s">&quot;MULTIPLY&quot;</span>
+    _sock(mix.inputs, <span class="s">&quot;Factor_Float&quot;</span>).default_value = <span class="n">1.0</span>
+    nt.links.new(ramp.outputs[<span class="s">&quot;Color&quot;</span>], _sock(mix.inputs, <span class="s">&quot;A_Color&quot;</span>))
+    nt.links.new(gain.outputs[<span class="s">&quot;Value&quot;</span>], _sock(mix.inputs, <span class="s">&quot;B_Color&quot;</span>))
+    nt.links.new(_sock(mix.outputs, <span class="s">&quot;Result_Color&quot;</span>), bsdf.inputs[<span class="s">&quot;Base Color&quot;</span>])
+    rough = nt.nodes.new(<span class="s">&quot;ShaderNodeMapRange&quot;</span>)
+    rough.inputs[<span class="s">&quot;To Min&quot;</span>].default_value = <span class="n">0.72</span>
+    rough.inputs[<span class="s">&quot;To Max&quot;</span>].default_value = <span class="n">0.52</span>
+    nt.links.new(noise.outputs[<span class="s">&quot;Fac&quot;</span>], rough.inputs[<span class="s">&quot;Value&quot;</span>])
+    nt.links.new(rough.outputs[<span class="s">&quot;Result&quot;</span>], bsdf.inputs[<span class="s">&quot;Roughness&quot;</span>])
+    <span class="k">return</span> mat
+
+
+<span class="k">def</span> clip_x(ring, x, keep_above):
+    <span class="s">&quot;&quot;&quot;Sutherland-Hodgman clip of a closed xy ring against the line X = x.&quot;&quot;&quot;</span>
+    out = []
+    n = len(ring)
+    <span class="k">for</span> i <span class="k">in</span> range(n):
+        p, q = ring[i], ring[(i + <span class="n">1</span>) % n]
+        p_in = p[<span class="n">0</span>] &gt;= x <span class="k">if</span> keep_above <span class="k">else</span> p[<span class="n">0</span>] &lt;= x
+        q_in = q[<span class="n">0</span>] &gt;= x <span class="k">if</span> keep_above <span class="k">else</span> q[<span class="n">0</span>] &lt;= x
+        <span class="k">if</span> p_in:
+            out.append(p)
+        <span class="k">if</span> p_in != q_in:
+            t = (x - p[<span class="n">0</span>]) / (q[<span class="n">0</span>] - p[<span class="n">0</span>])
+            out.append((x, p[<span class="n">1</span>] + t * (q[<span class="n">1</span>] - p[<span class="n">1</span>])))
+    <span class="c"># a cut landing on an existing vertex would leave a zero-length edge</span>
+    clean = []
+    <span class="k">for</span> p <span class="k">in</span> out:
+        <span class="k">if</span> <span class="k">not</span> clean <span class="k">or</span> math.dist(p, clean[-<span class="n">1</span>]) &gt; <span class="n">1e-4</span>:
+            clean.append(p)
+    <span class="k">if</span> len(clean) &gt; <span class="n">2</span> <span class="k">and</span> math.dist(clean[<span class="n">0</span>], clean[-<span class="n">1</span>]) &lt;= <span class="n">1e-4</span>:
+        clean.pop()
+    <span class="k">return</span> clean
+
+
+<span class="k">def</span> add_board_disk(bm, z0, z1, xy_ring, mat_idx, n_boards):
+    <span class="s">&quot;&quot;&quot;A head of ``n_boards`` boards, the outline cut across X with seams between.
+
+    Each board is the croze outline clipped to its strip, so the outer
+    edge of every board is still the croze and the head seats exactly
+    as the one-piece disk did.
+    &quot;&quot;&quot;</span>
+    xs = [p[<span class="n">0</span>] <span class="k">for</span> p <span class="k">in</span> xy_ring]
+    x_lo, x_hi = min(xs), max(xs)
+    w = (x_hi - x_lo) / n_boards
+    <span class="k">for</span> k <span class="k">in</span> range(n_boards):
+        ring = xy_ring
+        <span class="k">if</span> k &gt; <span class="n">0</span>:
+            ring = clip_x(ring, x_lo + k * w + BOARD_SEAM * <span class="n">0.5</span>, <span class="k">True</span>)
+        <span class="k">if</span> k &lt; n_boards - <span class="n">1</span>:
+            ring = clip_x(ring, x_lo + (k + <span class="n">1</span>) * w - BOARD_SEAM * <span class="n">0.5</span>, <span class="k">False</span>)
+        add_polygon_disk(bm, z0, z1, ring, mat_idx)
+
+
+<span class="k">def</span> board_audit(me, z_lo, z_hi):
+    <span class="s">&quot;&quot;&quot;Boards of the flat wooden disk between ``z_lo`` and ``z_hi``: count and seams.
+
+    A board is a thin wooden shell wide in plan. Sorted across X, the
+    seam is the gap between one board&#x27;s max X and the next one&#x27;s min X.
+    &quot;&quot;&quot;</span>
+    boards = []
+    <span class="k">for</span> g <span class="k">in</span> shells(me):
+        <span class="k">if</span> mat_of(me, g) != WOOD_IDX:
+            <span class="k">continue</span>
+        a = shell_aabb(me, g)
+        <span class="k">if</span> a[<span class="n">5</span>] - a[<span class="n">2</span>] &gt; <span class="n">0.06</span> <span class="k">or</span> max(a[<span class="n">3</span>] - a[<span class="n">0</span>], a[<span class="n">4</span>] - a[<span class="n">1</span>]) &lt; BOARD_MIN_SPAN:
+            <span class="k">continue</span>
+        <span class="k">if</span> <span class="k">not</span> (z_lo &lt;= <span class="n">0.5</span> * (a[<span class="n">2</span>] + a[<span class="n">5</span>]) &lt;= z_hi):
+            <span class="k">continue</span>
+        boards.append(a)
+    boards.sort(key=<span class="k">lambda</span> a: a[<span class="n">0</span>])
+    seams = [boards[i + <span class="n">1</span>][<span class="n">0</span>] - boards[i][<span class="n">3</span>] <span class="k">for</span> i <span class="k">in</span> range(len(boards) - <span class="n">1</span>)]
+    <span class="k">return</span> len(boards), seams
+
+
+<span class="k">def</span> barrel_materials():
+    <span class="s">&quot;&quot;&quot;(wood, iron): shared by the check, the render and inspection.&quot;&quot;&quot;</span>
+    wood = wood_material(<span class="s">&quot;BarrelWood&quot;</span>)
+    metal = principled(
+        <span class="s">&quot;BarrelHoop&quot;</span>, (<span class="n">0.17</span>, <span class="n">0.165</span>, <span class="n">0.155</span>, <span class="n">1.0</span>), <span class="n">0.80</span>, <span class="n">0.46</span>,
+        noise_scale=<span class="n">18.0</span>, wear=(<span class="n">0.20</span>, <span class="n">0.085</span>, <span class="n">0.032</span>, <span class="n">1.0</span>),
+    )
+    <span class="k">return</span> wood, metal
+
+
 <span class="k">def</span> body_plan(me):
     groups = shells(me)
     xs, ys, z0s, z1s = [], [], [], []
@@ -1151,23 +1354,20 @@ <h2>Source</h2>
     short_staves=<span class="k">False</span>,
     float_head=<span class="k">False</span>,
     round_band=<span class="k">False</span>,
+    one_piece_head=<span class="k">False</span>,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=<span class="k">True</span>)
     flags = dict(
         short_staves=short_staves,
         float_head=float_head,
         round_band=round_band,
+        one_piece_head=one_piece_head,
     )
     low = build_barrel_mesh(<span class="s">&quot;BarrelLow&quot;</span>, <span class="n">0.004</span>, <span class="n">2</span>, **flags)
     high = build_barrel_mesh(<span class="s">&quot;BarrelHigh&quot;</span>, <span class="n">0.004</span>, <span class="n">4</span>, **flags)
-    wood = principled(
-        <span class="s">&quot;BarrelWood&quot;</span>, (<span class="n">0.48</span>, <span class="n">0.22</span>, <span class="n">0.07</span>, <span class="n">1.0</span>), <span class="n">0.0</span>, <span class="n">0.50</span>,
-        noise_scale=<span class="n">7.0</span>, wear=(<span class="n">0.28</span>, <span class="n">0.14</span>, <span class="n">0.05</span>, <span class="n">1.0</span>),
-    )
-    metal = principled(
-        <span class="s">&quot;BarrelHoop&quot;</span>, (<span class="n">0.55</span>, <span class="n">0.53</span>, <span class="n">0.50</span>, <span class="n">1.0</span>), <span class="n">1.0</span>, <span class="n">0.28</span>,
-        noise_scale=<span class="n">5.0</span>, wear=(<span class="n">0.35</span>, <span class="n">0.32</span>, <span class="n">0.28</span>, <span class="n">1.0</span>),
-    )
+    wood, metal = barrel_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
     <span class="k">if</span> stray_vert:
@@ -1200,6 +1400,9 @@ <h2>Source</h2>
     sup = support_audit(low.data)
     bite_min, bite_max = hoop_seat(low.data, spans)
     hgap = head_gap(low.data, spans)
+    boards_bot, seams_bot = board_audit(low.data, <span class="n">0.0</span>, <span class="n">0.2</span>)
+    boards_top, seams_top = board_audit(low.data, HEIGHT - <span class="n">0.2</span>, HEIGHT + <span class="n">0.2</span>)
+    seams = seams_bot + seams_top
     dia, ht = body_plan(low.data)
     print(
         <span class="s">f&quot;</span><span class="s">measured hygiene loose_v=</span>{hyg[<span class="s">&#x27;loose_v&#x27;</span>]}<span class="s"> loose_e=</span>{hyg[<span class="s">&#x27;loose_e&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
@@ -1211,6 +1414,10 @@ <h2>Source</h2>
         <span class="s">f&quot;</span><span class="s">hoop_bite=</span>{bite_min:<span class="s">.5f</span>}<span class="s">..</span>{bite_max:<span class="s">.5f</span>}<span class="s"> head_gap=</span>{hgap:<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
         <span class="s">f&quot;</span><span class="s">body=</span>{dia:<span class="s">.4f</span>}<span class="s">x</span>{ht:<span class="s">.4f</span>}<span class="s">&quot;</span>
     )
+    print(
+        <span class="s">f&quot;</span><span class="s">measured head_boards=</span>{boards_bot}<span class="s">+</span>{boards_top}<span class="s"> </span><span class="s">&quot;</span>
+        <span class="s">f&quot;</span><span class="s">seams=</span>{min(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s">..</span>{max(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s">&quot;</span>
+    )
 
     img, tex = setup_bake_image(low, wood)
     <span class="k">if</span> img <span class="k">is</span> <span class="k">None</span>:
@@ -1238,6 +1445,10 @@ <h2>Source</h2>
         os.remove(export_path)
     export_unity(export_path, [low, collider])
     export_size = os.path.getsize(export_path) <span class="k">if</span> os.path.isfile(export_path) <span class="k">else</span> <span class="n">0</span>
+    <span class="c"># Blender points TMPDIR at the working directory, so the export must not</span>
+    <span class="c"># outlive the measurement.</span>
+    <span class="k">if</span> os.path.exists(export_path):
+        os.remove(export_path)
 
     print(<span class="s">f&quot;</span><span class="s">blender=</span>{tuple(bpy.app.version)}<span class="s"> skip_decimate=</span>{skip_decimate}<span class="s">&quot;</span>)
     print(
@@ -1352,6 +1563,19 @@ <h2>Source</h2>
             <span class="s">&quot;(--float-head is the designed fail)&quot;</span>,
             <span class="n">17</span>,
         ), <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>
+    <span class="k">if</span> (
+        boards_bot != HEAD_BOARDS
+        <span class="k">or</span> boards_top != HEAD_BOARDS
+        <span class="k">or</span> min(seams, default=<span class="n">0.0</span>) &lt; BOARD_SEAM_MIN
+        <span class="k">or</span> max(seams, default=<span class="n">99.0</span>) &gt; BOARD_SEAM_MAX
+    ):
+        <span class="k">return</span> fail(
+            <span class="s">f&quot;</span><span class="s">head boards </span>{boards_bot}<span class="s">+</span>{boards_top}<span class="s"> != </span>{HEAD_BOARDS}<span class="s"> each, or </span><span class="s">&quot;</span>
+            <span class="s">f&quot;</span><span class="s">seams </span>{min(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s">..</span>{max(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
+            <span class="s">f&quot;</span><span class="s">outside [</span>{BOARD_SEAM_MIN}<span class="s">, </span>{BOARD_SEAM_MAX}<span class="s">] </span><span class="s">&quot;</span>
+            <span class="s">&quot;(--one-piece-head is the designed fail)&quot;</span>,
+            <span class="n">17</span>,
+        ), <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>
     <span class="k">if</span> bite_min &lt; HOOP_BITE_MIN <span class="k">or</span> bite_max &gt; HOOP_BITE_MAX:
         <span class="k">return</span> fail(
             <span class="s">f&quot;</span><span class="s">hoop bite </span>{bite_min:<span class="s">.5f</span>}<span class="s">..</span>{bite_max:<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
@@ -1482,6 +1706,7 @@ <h2>Source</h2>
     p.add_argument(<span class="s">&quot;--short-staves&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     p.add_argument(<span class="s">&quot;--float-head&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     p.add_argument(<span class="s">&quot;--round-band&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
+    p.add_argument(<span class="s">&quot;--one-piece-head&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1491,6 +1716,7 @@ <h2>Source</h2>
         short_staves=args.short_staves,
         float_head=args.float_head,
         round_band=args.round_band,
+        one_piece_head=args.one_piece_head,
     )
     <span class="k">if</span> code:
         <span class="k">return</span> code
@@ -1515,7 +1741,7 @@ <h2>Source</h2>
   </main>
   <dialog class="lightbox" id="lightbox" aria-label="Full-size render">
     <button class="lightbox-close" type="button" autofocus>Close</button>
-    <img src="../assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by three metal hoops." />
+    <img src="../assets/wooden-barrel-hero.webp" alt="A wooden stave barrel bound by four iron hoops, its head made of boards." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/wooden-bucket/index.html b/docs/gallery/wooden-bucket/index.html
index 1456caf9..b22439fa 100644
--- a/docs/gallery/wooden-bucket/index.html
+++ b/docs/gallery/wooden-bucket/index.html
@@ -4,25 +4,25 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1" />
   <title>wooden-bucket — Showcase — Blender Developer Tools</title>
-  <meta name="description" content="A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta name="description" content="A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
   <link rel="canonical" href="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/wooden-bucket/" />
   <link rel="icon" href="../../assets/favicon.svg" type="image/svg+xml" />
   <meta name="theme-color" content="#1a1b1e" />
   <meta name="color-scheme" content="dark" />
   <meta property="og:type" content="website" />
   <meta property="og:title" content="wooden-bucket — Showcase — Blender Developer Tools" />
-  <meta property="og:description" content="A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta property="og:description" content="A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
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   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A wooden stave bucket with metal hoops and a curved wooden bail handle." />
+  <meta property="og:image:alt" content="A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings." />
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-  <meta name="twitter:description" content="A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
+  <meta name="twitter:description" content="A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/wooden-bucket-hero.webp" />
-  <meta name="twitter:image:alt" content="A wooden stave bucket with metal hoops and a curved wooden bail handle." />
+  <meta name="twitter:image:alt" content="A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings." />
   <style>
     /* fonts are deployed by the landing build (docs/fonts/) */
     @font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
@@ -265,36 +265,41 @@
   </div>
   <header class="hero">
     <h1>wooden-bucket</h1>
-    <p>A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+    <p>A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A wooden stave bucket with metal hoops and a curved wooden bail handle.">
-      <img src="../assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with metal hoops and a curved wooden bail handle." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings.">
+      <img src="../assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings." width="1280" height="720" />
     </button>
     <p class="zoom-hint">Rendered headless by the showcase piece itself — click to zoom.</p>
-    <div class="callout"><span class="tag">witnesses</span> Recomputed: 4872 tris, three materials with 1424 wood, 1020 metal, and 208 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.383×0.346×0.527 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0013 m, LOD ratios in band, convex collider 302 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget.</div>
+    <div class="callout"><span class="tag">witnesses</span> Recomputed: 5458 tris, three materials with 1448 wood, 1020 metal, and 486 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.396×0.346×0.534 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0011 m, three bottom boards, no rope vertex inside an ear plate, LOD ratios in band, convex collider 276 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget; --sunk-rope exits 17 on the rope-clearance budget.</div>
     <div class="runline">
       <pre id="runCmd">blender --background --python showcase/wooden-bucket/wooden_bucket.py --</pre>
       <button class="copy-btn" id="copyRun" type="button">Copy</button>
     </div>
     <section class="detail-section md">
-<p>A showcase piece, not an example. Procedural coopered pail (16 staves with seeded width jitter, a bottom seated in a croze above a chime, iron hoops lofted on the stave faces, ear plates and rings, a round rope bail through the rings) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.</p>
-<p>Hoops evaluate the same <code>host_outer_r</code> chord as the stave flats. <code>--round-band</code> is the falsifier: a circle of <code>radius_at(z)</code> instead of the chord. The floor follows the inner stave polygon. Ear plates sit on the outer stave face below the rim; the bail is a semicircle whose ends pass through the rings. <code>--float-handle</code> shrinks that semicircle so the bar sits on the ring; <code>--float-bottom</code> shrinks the floor out of the croze.</p>
+<p>A showcase piece, not an example. Procedural coopered pail (16 staves with seeded width jitter, a bottom of three boards seated in a croze above a chime, iron hoops lofted on the stave faces, ear plates and rings, a three-strand rope bail through the rings) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.</p>
+<p>Hoops evaluate the same <code>host_outer_r</code> chord as the stave flats. <code>--round-band</code> is the falsifier: a circle of <code>radius_at(z)</code> instead of the chord. The floor follows the inner stave polygon. Ear plates sit on the outer stave face below the rim; the bail is a semicircle whose ends pass through the rings and run on below them. <code>--float-handle</code> shrinks that semicircle and lifts it by what it lost, so the envelope stays put and only the bail-ear gap fails; <code>--float-bottom</code> shrinks the floor out of the croze.</p>
 <p>It asserts <strong>budget conformance</strong> of the generated result. It does not witness an API contract. &quot;It rendered without error&quot; is not a check.</p>
 <p><strong>Composes</strong> skills <code>mesh-editing-and-bmesh</code>, <code>bake-high-to-low</code>, <code>depsgraph-and-evaluated-data</code>, <code>engine-export-presets</code>, and snippets <code>bake_normal_high_to_low.py</code>, <code>setup_bake_target_image.py</code>, <code>lod_chain.py</code> / <code>decimate_to_budget.py</code>, <code>convex_hull_collider.py</code>, <code>export_preset_unity.py</code> (helpers copied, not imported as a package).</p>
 <h2>Budgets</h2>
 <p>Declared as named constants; every gate <strong>recomputes</strong> from the mesh, materials, UVs, evaluated LOD, collider, or export file.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (4.5.11 / 5.1.2 / 5.2.1)</th></tr></thead><tbody><tr><td>Base triangles</td><td>4000–5800</td><td>4872 / 4872 / 4872</td></tr><tr><td>LOD1 ratio</td><td>0.32–0.62 of base</td><td>0.5000 / 0.5000 / 0.5000</td></tr><tr><td>LOD2 ratio</td><td>0.10–0.35 of base</td><td>0.2196 / 0.2196 / 0.2188</td></tr><tr><td>Materials</td><td>exactly 3 distinct; ≥350 wood, ≥180 metal, ≥40 rope</td><td>3 slots; 1424 / 1020 / 208</td></tr><tr><td>UVs</td><td>in <code>0..1</code>, AABB overlap ≤ 1e-5</td><td>in range, overlap 0</td></tr><tr><td>Outer AABB</td><td>(0.383, 0.346, 0.527) m ± 0.015</td><td>(0.3832, 0.3462, 0.5271), zmin 0</td></tr><tr><td>Collider tris</td><td>≤ 420</td><td>302</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>378296 / 378296 / 378276 bytes</td></tr></tbody></table></div>
-<p>Base triangles rose from <strong>4272 to 4872</strong> in the quality pass: overlapping identical staves, circular hoops, and a 12-box bail became 16 jittered staves, chord-seated hoops, a polygonal croze floor, and a round bail through the ear rings.</p>
-<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — 5.2.1 is 4 tris leaner on LOD2. The gate is a ratio band, not an exact count. Bake pixels are stochastic; the gate is <code>has_data</code> plus operator <code>FINISHED</code>, not byte-identity. Stave-width jitter uses fixed seed 17. Export byte counts differ by 20 B on 5.2.1 (glTF serializer), not a gated axis.</p>
+<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (4.5.11 / 5.1.2 / 5.2.1)</th></tr></thead><tbody><tr><td>Base triangles</td><td>4000–5800</td><td>5458 / 5458 / 5458</td></tr><tr><td>LOD1 ratio</td><td>0.32–0.62 of base</td><td>0.4998 / 0.4998 / 0.4998</td></tr><tr><td>LOD2 ratio</td><td>0.10–0.35 of base</td><td>0.2199 / 0.2199 / 0.2191</td></tr><tr><td>Materials</td><td>exactly 3 distinct; ≥350 wood, ≥180 metal, ≥40 rope</td><td>3 slots; 1448 / 1020 / 486</td></tr><tr><td>UVs</td><td>in <code>0..1</code>, AABB overlap ≤ 1e-5</td><td>in range, overlap 0</td></tr><tr><td>Outer AABB</td><td>(0.396, 0.346, 0.534) m ± 0.015</td><td>(0.3957, 0.3462, 0.5338), zmin 0</td></tr><tr><td>Collider tris</td><td>≤ 420</td><td>276</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>420984 / 420984 / 420976 bytes</td></tr></tbody></table></div>
+<p>Base triangles rose from <strong>4272 to 4872</strong> in the quality pass: overlapping identical staves, circular hoops, and a 12-box bail became 16 jittered staves, chord-seated hoops, a polygonal croze floor, and a round bail through the ear rings. The second pass took it to <strong>5458</strong>: the bail became three-strand rope (48 segments of a nine-vertex lobed section, running on through the rings) and the floor three boards.</p>
+<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series, so LOD2 ratios differ slightly between versions. The gate is a ratio band, not an exact count. Bake pixels are stochastic; the gate is <code>has_data</code> plus operator <code>FINISHED</code>, not byte-identity. Stave-width jitter uses fixed seed 17. Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis.</p>
 <h3>Hygiene</h3>
 <p>Recomputed from the generated mesh, not asserted about the script.</p>
 <div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Non-manifold edges</td><td>0</td><td>0</td></tr><tr><td>Loose verts / edges</td><td>0 / 0</td><td>0 / 0</td></tr><tr><td>Doubles merged at 1e-5</td><td>0</td><td>0</td></tr><tr><td>Zero-area faces</td><td>0</td><td>0</td></tr><tr><td>N-gons</td><td>0</td><td>0</td></tr><tr><td>Coplanar disjoint face pairs</td><td>0</td><td>0</td></tr><tr><td>Grounded: <code>zmin</code></td><td>within 1e-4 of 0</td><td>0.0000</td></tr><tr><td>Named supports: 16 staves</td><td>each <code>zmin</code> ≤ 0.001</td><td>16, stave_z 0.00000</td></tr><tr><td>Body plan</td><td>0.335 m dia × 0.360 m high ± 0.04</td><td>0.3349 × 0.3600</td></tr></tbody></table></div>
 <h3>Joint fit and seat</h3>
-<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Bail-ear BVH gap</td><td>≤ 0.006 m</td><td>0.00125</td></tr><tr><td>Floor-croze rim BVH gap</td><td>≤ 0.008 m</td><td>0.00458</td></tr><tr><td>Hoop bite (host r − inner hoop r)</td><td>0.0010–0.007 m</td><td>0.00250</td></tr></tbody></table></div>
+<div class="table-wrap"><table><thead><tr><th scope="col">Axis</th><th scope="col">Declared</th><th scope="col">Measured (all three)</th></tr></thead><tbody><tr><td>Bail-ear BVH gap</td><td>≤ 0.006 m</td><td>0.00107</td></tr><tr><td>Floor-croze rim BVH gap</td><td>≤ 0.008 m</td><td>0.00474</td></tr><tr><td>Bottom boards</td><td>3; every seam 0.0006–0.0025 m</td><td>3; 0.00120</td></tr><tr><td>Rope clears the ear plates</td><td>2 plates; 0 rope vertices inside either</td><td>2; 0</td></tr><tr><td>Hoop bite (host r − inner hoop r)</td><td>0.0010–0.007 m</td><td>0.00250</td></tr></tbody></table></div>
 <h3>Falsifiers</h3>
-<p>Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Flag</th><th scope="col">Budget violated</th><th scope="col">Exit</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td></tr><tr><td><code>--stray-vert</code></td><td>loose vertex count is 0</td><td>15</td></tr><tr><td><code>--lift-z</code></td><td>bounding box <code>zmin</code> is 0</td><td>16</td></tr><tr><td><code>--short-staves</code></td><td>named stave supports at Z=0</td><td>16</td></tr><tr><td><code>--float-handle</code></td><td>bail-ear gap</td><td>17</td></tr><tr><td><code>--float-bottom</code></td><td>floor-croze gap</td><td>17</td></tr><tr><td><code>--round-band</code></td><td>hoop bite band</td><td>18</td></tr></tbody></table></div>
+<p>Each violates one named budget. All nine were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.</p>
+<div class="table-wrap"><table><thead><tr><th scope="col">Flag</th><th scope="col">Budget violated</th><th scope="col">Exit</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td></tr><tr><td><code>--stray-vert</code></td><td>loose vertex count is 0</td><td>15</td></tr><tr><td><code>--lift-z</code></td><td>bounding box <code>zmin</code> is 0</td><td>16</td></tr><tr><td><code>--short-staves</code></td><td>named stave supports at Z=0</td><td>16</td></tr><tr><td><code>--float-handle</code></td><td>bail-ear gap</td><td>17</td></tr><tr><td><code>--float-bottom</code></td><td>floor-croze gap</td><td>17</td></tr><tr><td><code>--round-band</code></td><td>hoop bite band</td><td>18</td></tr><tr><td><code>--one-piece-bottom</code></td><td>bottom boards: 3</td><td>17</td></tr><tr><td><code>--sunk-rope</code></td><td>rope clears the ear plates</td><td>17</td></tr></tbody></table></div>
+<h2>Rope and ears</h2>
+<p>The bail was a smooth eight-sided tube in a rope material, and it read as a plastic hose. It is now laid rope: a three-lobed section turned one vertex step per ring, so the lobes wind along the bail as strands. The section&#x27;s frame is fixed to the bail&#x27;s plane, so the lay does not jump where the ends turn vertical.</p>
+<p>The ring offset from the ear plate was <code>RING_MAJOR * 0.25</code>, which put the rope&#x27;s axis 3.25 mm off the plate and its body through it (hidden by the ring in the old stills). The offset is now sized from the rope&#x27;s lobes plus 0.5 mm, and <strong>Rope clears the ear plates</strong> asserts it. <code>--sunk-rope</code> restores the old offset and puts 19 rope vertices inside a plate. The outer AABB was re-fitted to the honest envelope: 12.5 mm wider across the ears and 6 mm taller.</p>
+<h2>Surface</h2>
+<p>Every stave and board carries a seeded <code>PlankTone</code> and a <code>GrainDir</code> (its own long axis) as face attributes, and <code>wood_material</code> stretches grain along that axis. The hoops, plates and rings are dark rusted iron. The temp <code>.glb</code> is removed once its size is measured.</p>
 <h2>Run</h2>
 <pre><code>blender --background --python wooden_bucket.py --
 blender --background --python wooden_bucket.py -- --skip-decimate
@@ -304,11 +309,13 @@ <h2>Run</h2>
 blender --background --python wooden_bucket.py -- --float-handle
 blender --background --python wooden_bucket.py -- --float-bottom
 blender --background --python wooden_bucket.py -- --round-band
+blender --background --python wooden_bucket.py -- --one-piece-bottom
+blender --background --python wooden_bucket.py -- --sunk-rope
 blender --background --python wooden_bucket.py -- --output bucket.png</code></pre>
 <p>Smoke passes no flags.</p>
 <h2>Exit codes</h2>
 <p>File-local. <code>9</code> is a valid check code. <code>10</code> is reserved for <code>gallery_framing.check_framing</code> on the <code>--output</code> path. <code>15</code>–<code>19</code> are the hygiene and joint-fit family.</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Code</th><th scope="col">Meaning</th></tr></thead><tbody><tr><td>0</td><td>Success</td></tr><tr><td>1</td><td>Uncaught exception (FATAL wrapper)</td></tr><tr><td>2</td><td>argparse / usage</td></tr><tr><td>3</td><td>Mesh did not build / no UV layer</td></tr><tr><td>4</td><td>Base triangle count outside range</td></tr><tr><td>5</td><td>Material count ≠ 3 distinct slots, or a face-count floor missed</td></tr><tr><td>6</td><td>UVs outside 0..1</td></tr><tr><td>7</td><td>UV AABB overlap above tolerance</td></tr><tr><td>8</td><td>World AABB off declared outer size</td></tr><tr><td>9</td><td>LOD ratio band (<code>--skip-decimate</code> lands here)</td></tr><tr><td>10</td><td>Framing gate (render path only)</td></tr><tr><td>11</td><td>Collider triangle count above ceiling</td></tr><tr><td>12</td><td>Bake did not finish or image has no data</td></tr><tr><td>13</td><td>Export file missing or empty</td></tr><tr><td>14</td><td><code>--output</code> produced no file</td></tr><tr><td>15</td><td>Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight</td></tr><tr><td>16</td><td>Not grounded: bounding box <code>zmin</code> off 0, or a named stave floats</td></tr><tr><td>17</td><td>Joint fit: bail-ear gap or floor-croze gap</td></tr><tr><td>18</td><td>Seat: hoop bite band (<code>--round-band</code>)</td></tr><tr><td>19</td><td>Body diameter or height off the stated real-world size</td></tr></tbody></table></div>
+<div class="table-wrap"><table><thead><tr><th scope="col">Code</th><th scope="col">Meaning</th></tr></thead><tbody><tr><td>0</td><td>Success</td></tr><tr><td>1</td><td>Uncaught exception (FATAL wrapper)</td></tr><tr><td>2</td><td>argparse / usage</td></tr><tr><td>3</td><td>Mesh did not build / no UV layer</td></tr><tr><td>4</td><td>Base triangle count outside range</td></tr><tr><td>5</td><td>Material count ≠ 3 distinct slots, or a face-count floor missed</td></tr><tr><td>6</td><td>UVs outside 0..1</td></tr><tr><td>7</td><td>UV AABB overlap above tolerance</td></tr><tr><td>8</td><td>World AABB off declared outer size</td></tr><tr><td>9</td><td>LOD ratio band (<code>--skip-decimate</code> lands here)</td></tr><tr><td>10</td><td>Framing gate (render path only)</td></tr><tr><td>11</td><td>Collider triangle count above ceiling</td></tr><tr><td>12</td><td>Bake did not finish or image has no data</td></tr><tr><td>13</td><td>Export file missing or empty</td></tr><tr><td>14</td><td><code>--output</code> produced no file</td></tr><tr><td>15</td><td>Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight</td></tr><tr><td>16</td><td>Not grounded: bounding box <code>zmin</code> off 0, or a named stave floats</td></tr><tr><td>17</td><td>Joint fit: bail-ear gap, floor-croze gap, bottom boards and seams, or rope through an ear plate</td></tr><tr><td>18</td><td>Seat: hoop bite band (<code>--round-band</code>)</td></tr><tr><td>19</td><td>Body diameter or height off the stated real-world size</td></tr></tbody></table></div>
     </section>
     <section class="detail-section src">
       <h2>Source</h2>
@@ -334,7 +341,8 @@ <h2>Source</h2>
 budget: ``--skip-decimate`` the LOD-ratio band, ``--stray-vert`` mesh
 hygiene, ``--lift-z`` grounded zmin, ``--short-staves`` named stave
 supports, ``--float-handle`` bail-ear joint-fit, ``--float-bottom``
-floor-croze joint-fit, ``--round-band`` hoop seat (hoop generated on a
+floor-croze joint-fit, ``--one-piece-bottom`` bottom boards (one slab
+instead of boards), ``--round-band`` hoop seat (hoop generated on a
 circle instead of the stave chords).
 
 Fixed seed 17 for stave-width jitter. DECIMATE COLLAPSE triangle counts
@@ -387,12 +395,23 @@ <h2>Source</h2>
 CHIME = <span class="n">0.008</span>
 CROZE_BITE = <span class="n">0.0025</span>
 FLOOR_GAP_MAX = <span class="n">0.008</span>
-BAIL_R = <span class="n">0.008</span>
-BAIL_SEGS = <span class="n">24</span>
-BAIL_PIPE = <span class="n">8</span>
+BAIL_R = <span class="n">0.0075</span>
+BAIL_SEGS = <span class="n">48</span>
+<span class="c"># The bail is three-strand rope: a three-lobed section of ROPE_PIPE verts</span>
+<span class="c"># turned one vertex step per ring, so the lobes run as helical strands.</span>
+<span class="c"># Lobes reach BAIL_R * (1 + ROPE_LOBE), inside the ear ring&#x27;s hole</span>
+<span class="c"># (RING_MAJOR - RING_MINOR). Each end runs ROPE_TAIL on through its ring.</span>
+<span class="c"># The ring centre stands ROPE_CLEAR beyond the rope&#x27;s lobes off the ear</span>
+<span class="c"># plate, so the rope passes the plate instead of through it.</span>
+ROPE_PIPE = <span class="n">9</span>
+ROPE_LOBE = <span class="n">0.20</span>
+ROPE_TAIL = <span class="n">0.014</span>
+ROPE_CLEAR = <span class="n">0.0005</span>
 EAR_Z = HEIGHT - <span class="n">0.016</span>
 RING_MAJOR = <span class="n">0.013</span>
 RING_MINOR = <span class="n">0.0035</span>
+RING_OFFSET = BAIL_R * (<span class="n">1.0</span> + ROPE_LOBE) + ROPE_CLEAR
+SUNK_RING_OFFSET = RING_MAJOR * <span class="n">0.25</span>
 BAIL_GAP_MAX = <span class="n">0.006</span>
 STAVE_ZMIN_MAX = <span class="n">0.001</span>
 SHORT_STAVES_LIFT = <span class="n">0.040</span>
@@ -406,7 +425,7 @@ <h2>Source</h2>
 BODY_DIA = <span class="n">0.335</span>
 BODY_H = <span class="n">0.360</span>
 BBOX_TOL = <span class="n">0.015</span>
-OUTER_SIZE = (<span class="n">0.383</span>, <span class="n">0.346</span>, <span class="n">0.527</span>)
+OUTER_SIZE = (<span class="n">0.396</span>, <span class="n">0.346</span>, <span class="n">0.534</span>)
 
 BASE_TRIS_MIN = <span class="n">4000</span>
 BASE_TRIS_MAX = <span class="n">5800</span>
@@ -431,6 +450,19 @@ <h2>Source</h2>
 METAL_IDX = <span class="n">1</span>
 ROPE_IDX = <span class="n">2</span>
 
+<span class="c"># The bottom is BOTTOM_BOARDS boards cut across X from the croze outline,</span>
+<span class="c"># with a BOARD_SEAM between neighbours. A board is a thin wooden shell at</span>
+<span class="c"># least BOARD_MIN_SPAN wide in plan (the narrowest board is 0.20).</span>
+BOTTOM_BOARDS = <span class="n">3</span>
+BOARD_SEAM = <span class="n">0.0012</span>
+BOARD_SEAM_MIN = <span class="n">0.0006</span>
+BOARD_SEAM_MAX = <span class="n">0.0025</span>
+BOARD_MIN_SPAN = <span class="n">0.15</span>
+<span class="c"># Per-piece wood tone jitter and grain frequency, as in shipping-crate.</span>
+PLANK_TONE_JITTER = <span class="n">0.28</span>
+TONE_SEED = <span class="n">29</span>
+WOOD_GRAIN_SCALE = <span class="n">45.0</span>
+
 
 <span class="k">def</span> eevee_engine_id():
     <span class="k">return</span> <span class="s">&quot;BLENDER_EEVEE&quot;</span> <span class="k">if</span> bpy.app.version &gt;= (<span class="n">5</span>, <span class="n">0</span>, <span class="n">0</span>) <span class="k">else</span> <span class="s">&quot;BLENDER_EEVEE_NEXT&quot;</span>
@@ -590,7 +622,15 @@ <h2>Source</h2>
     <span class="k">return</span> verts
 
 
-<span class="k">def</span> add_pipe_curve(bm, points, radius, segs, mat_idx):
+<span class="k">def</span> add_rope_curve(bm, points, radius, mat_idx):
+    <span class="s">&quot;&quot;&quot;Three-strand rope along a path in the XZ plane.
+
+    The section is ROPE_PIPE verts with three lobes, turned one vertex
+    step per ring, so each lobe winds along the path as a strand. The
+    frame is fixed to the path&#x27;s plane (side = +Y), so the lay never
+    jumps where the path turns vertical.
+    &quot;&quot;&quot;</span>
+    side = Vector((<span class="n">0.0</span>, <span class="n">1.0</span>, <span class="n">0.0</span>))
     rings = []
     n = len(points)
     <span class="k">for</span> i, p <span class="k">in</span> enumerate(points):
@@ -599,20 +639,13 @@ <h2>Source</h2>
             tangent = (Vector(points[i + <span class="n">1</span>]) - p).normalized()
         <span class="k">else</span>:
             tangent = (p - Vector(points[i - <span class="n">1</span>])).normalized()
-        side = Vector((-tangent.y, tangent.x, <span class="n">0.0</span>))
-        <span class="k">if</span> side.length &lt; <span class="n">1e-6</span>:
-            side = Vector((<span class="n">1.0</span>, <span class="n">0.0</span>, <span class="n">0.0</span>))
-        <span class="k">else</span>:
-            side.normalize()
         up = tangent.cross(side).normalized()
         ring = []
-        <span class="k">for</span> k <span class="k">in</span> range(segs):
-            a = <span class="n">2.0</span> * math.pi * k / segs
-            ring.append(
-                bm.verts.new(
-                    p + side * (radius * math.cos(a)) + up * (radius * math.sin(a))
-                )
-            )
+        <span class="k">for</span> k <span class="k">in</span> range(ROPE_PIPE):
+            a = <span class="n">2.0</span> * math.pi * k / ROPE_PIPE
+            lobe = <span class="n">1.0</span> + ROPE_LOBE * math.cos(<span class="n">3.0</span> * a - <span class="n">2.0</span> * math.pi * <span class="n">3.0</span> * i / ROPE_PIPE)
+            r = radius * lobe
+            ring.append(bm.verts.new(p + side * (r * math.cos(a)) + up * (r * math.sin(a))))
         rings.append(ring)
     loft_rings(bm, rings, mat_idx, cap_start=<span class="k">True</span>, cap_end=<span class="k">True</span>)
 
@@ -726,7 +759,7 @@ <h2>Source</h2>
         bmesh.ops.triangulate(bm, faces=faces)
 
 
-<span class="k">def</span> add_ears_and_bail(bm, spans, float_handle):
+<span class="k">def</span> add_ears_and_bail(bm, spans, float_handle, sunk_rope=<span class="k">False</span>):
     <span class="s">&quot;&quot;&quot;Ear plates + flat rings (hole along Z) and a round bail through them.
 
     Ring centres sit on the stave outer at EAR_Z. The bail is a semicircle
@@ -743,8 +776,11 @@ <h2>Source</h2>
     plate_z = HEIGHT - plate_h * <span class="n">0.5</span> - <span class="n">0.006</span>
     x_l = -(r_l + plate_t * <span class="n">0.5</span>)
     x_r = r_r + plate_t * <span class="n">0.5</span>
-    ring_x_l = -(r_l + plate_t + RING_MAJOR * <span class="n">0.25</span>)
-    ring_x_r = r_r + plate_t + RING_MAJOR * <span class="n">0.25</span>
+    <span class="c"># --sunk-rope restores the old offset, a quarter of the ring&#x27;s major</span>
+    <span class="c"># radius: the rope&#x27;s axis 3 mm off the plate, its body through it.</span>
+    off = SUNK_RING_OFFSET <span class="k">if</span> sunk_rope <span class="k">else</span> RING_OFFSET
+    ring_x_l = -(r_l + plate_t + off)
+    ring_x_r = r_r + plate_t + off
     <span class="k">for</span> x <span class="k">in</span> (x_l, x_r):
         add_box(
             bm,
@@ -765,15 +801,21 @@ <h2>Source</h2>
         )
     rx = <span class="n">0.5</span> * (abs(ring_x_l) + abs(ring_x_r))
     <span class="k">if</span> float_handle:
+        <span class="c"># a smaller bail lifted by exactly what it lost, so its top and the</span>
+        <span class="c"># envelope stay put and only the bail-ear gap fails</span>
+        z0 = EAR_Z + <span class="n">0.28</span> * rx
         rx *= <span class="n">0.72</span>
-        z0 = EAR_Z + <span class="n">0.035</span>
     <span class="k">else</span>:
         z0 = EAR_Z
-    pts = []
+    <span class="c"># below each ring the rope runs on down ROPE_TAIL, so it passes</span>
+    <span class="c"># through the ring instead of stopping inside it</span>
+    tail = (-ROPE_TAIL, -<span class="n">0.5</span> * ROPE_TAIL)
+    pts = [(rx, <span class="n">0.0</span>, z0 + dz) <span class="k">for</span> dz <span class="k">in</span> tail]
     <span class="k">for</span> i <span class="k">in</span> range(BAIL_SEGS + <span class="n">1</span>):
         t = math.pi * i / BAIL_SEGS
         pts.append((rx * math.cos(t), <span class="n">0.0</span>, z0 + rx * math.sin(t)))
-    add_pipe_curve(bm, pts, BAIL_R, BAIL_PIPE, ROPE_IDX)
+    pts.extend((-rx, <span class="n">0.0</span>, z0 + dz) <span class="k">for</span> dz <span class="k">in</span> reversed(tail))
+    add_rope_curve(bm, pts, BAIL_R, ROPE_IDX)
 
 
 <span class="k">def</span> pack_uvs(bm, margin=<span class="n">0.08</span>):
@@ -825,6 +867,8 @@ <h2>Source</h2>
     float_handle=<span class="k">False</span>,
     round_band=<span class="k">False</span>,
     float_bottom=<span class="k">False</span>,
+    one_piece_bottom=<span class="k">False</span>,
+    sunk_rope=<span class="k">False</span>,
 ):
     bm = bmesh.new()
     gap_ang = GAP_M / max(R_TOP, <span class="n">0.1</span>)
@@ -835,13 +879,13 @@ <h2>Source</h2>
         bot_z0 = CHIME
         bot_z1 = CHIME + BOTTOM_T
         shrink = <span class="n">0.022</span> <span class="k">if</span> float_bottom <span class="k">else</span> <span class="n">0.0</span>
-        add_polygon_disk(
+        add_board_disk(
             bm, bot_z0, bot_z1,
             croze_xy(spans, <span class="n">0.5</span> * (bot_z0 + bot_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, <span class="n">1</span> <span class="k">if</span> one_piece_bottom <span class="k">else</span> BOTTOM_BOARDS,
         )
         build_hoops(bm, spans, round_band)
-        add_ears_and_bail(bm, spans, float_handle)
+        add_ears_and_bail(bm, spans, float_handle, sunk_rope)
         triangulate_ngons(bm)
         pack_uvs(bm)
         bmesh.ops.recalc_face_normals(bm, faces=list(bm.faces))
@@ -1076,8 +1120,7 @@ <h2>Source</h2>
             <span class="k">continue</span>
         a = shell_aabb(me, g)
         dz = a[<span class="n">5</span>] - a[<span class="n">2</span>]
-        r = <span class="n">0.25</span> * ((a[<span class="n">3</span>] - a[<span class="n">0</span>]) + (a[<span class="n">4</span>] - a[<span class="n">1</span>]))
-        <span class="k">if</span> dz &lt; <span class="n">0.05</span> <span class="k">and</span> r &gt; <span class="n">0.08</span>:
+        <span class="k">if</span> dz &lt; <span class="n">0.05</span> <span class="k">and</span> max(a[<span class="n">3</span>] - a[<span class="n">0</span>], a[<span class="n">4</span>] - a[<span class="n">1</span>]) &gt;= BOARD_MIN_SPAN:
             floors.append(g)
         <span class="k">elif</span> dz &gt; <span class="n">0.20</span>:
             staves.append(g)
@@ -1149,6 +1192,221 @@ <h2>Source</h2>
         bm_b.free()
 
 
+<span class="k">def</span> _long_axis(pts):
+    <span class="s">&quot;&quot;&quot;Principal axis of a point set, by power iteration on its covariance.&quot;&quot;&quot;</span>
+    c = sum(pts, Vector()) / len(pts)
+    cov = [[<span class="n">0.0</span>] * <span class="n">3</span> <span class="k">for</span> _ <span class="k">in</span> range(<span class="n">3</span>)]
+    <span class="k">for</span> p <span class="k">in</span> pts:
+        d = p - c
+        <span class="k">for</span> i <span class="k">in</span> range(<span class="n">3</span>):
+            <span class="k">for</span> j <span class="k">in</span> range(<span class="n">3</span>):
+                cov[i][j] += d[i] * d[j]
+    v = Vector((<span class="n">1.0</span>, <span class="n">0.3</span>, <span class="n">0.1</span>))
+    <span class="k">for</span> _ <span class="k">in</span> range(<span class="n">30</span>):
+        w = Vector([sum(cov[i][j] * v[j] <span class="k">for</span> j <span class="k">in</span> range(<span class="n">3</span>)) <span class="k">for</span> i <span class="k">in</span> range(<span class="n">3</span>)])
+        <span class="k">if</span> w.length &lt; <span class="n">1e-12</span>:
+            <span class="k">break</span>
+        v = w.normalized()
+    <span class="k">return</span> v
+
+
+<span class="k">def</span> paint_planks(me):
+    <span class="s">&quot;&quot;&quot;Per-shell ``PlankTone`` and ``GrainDir`` face attributes for the wood shader.
+
+    Every stave and every board is its own shell, so each gets one tone and
+    grain running along its own long axis (up the curved staves, across
+    the flat boards).
+    &quot;&quot;&quot;</span>
+    tone = [<span class="n">0.5</span>] * len(me.polygons)
+    grain = [(<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.0</span>)] * len(me.polygons)
+    owner = {}
+    rng = random.Random(TONE_SEED)
+    <span class="k">for</span> g <span class="k">in</span> shells(me):
+        pts = [me.vertices[i].co.copy() <span class="k">for</span> i <span class="k">in</span> g]
+        d = _long_axis(pts) <span class="k">if</span> len(pts) &gt; <span class="n">2</span> <span class="k">else</span> Vector((<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">1.0</span>))
+        t = <span class="n">0.5</span> + rng.uniform(-PLANK_TONE_JITTER, PLANK_TONE_JITTER)
+        <span class="k">for</span> i <span class="k">in</span> g:
+            owner[i] = (t, tuple(d))
+    <span class="k">for</span> poly <span class="k">in</span> me.polygons:
+        t, d = owner[poly.vertices[<span class="n">0</span>]]
+        tone[poly.index] = t
+        grain[poly.index] = d
+    a = me.attributes.new(<span class="s">&quot;PlankTone&quot;</span>, <span class="s">&quot;FLOAT&quot;</span>, <span class="s">&quot;FACE&quot;</span>)
+    a.data.foreach_set(<span class="s">&quot;value&quot;</span>, tone)
+    b = me.attributes.new(<span class="s">&quot;GrainDir&quot;</span>, <span class="s">&quot;FLOAT_VECTOR&quot;</span>, <span class="s">&quot;FACE&quot;</span>)
+    b.data.foreach_set(<span class="s">&quot;vector&quot;</span>, [c <span class="k">for</span> v <span class="k">in</span> grain <span class="k">for</span> c <span class="k">in</span> v])
+
+
+<span class="k">def</span> _sock(sockets, identifier):
+    <span class="s">&quot;&quot;&quot;A Mix-node socket by identifier; its A/B/Result names repeat per type.&quot;&quot;&quot;</span>
+    <span class="k">return</span> next(sk <span class="k">for</span> sk <span class="k">in</span> sockets <span class="k">if</span> sk.identifier == identifier)
+
+
+<span class="k">def</span> wood_material(name):
+    <span class="s">&quot;&quot;&quot;Grain along each stave or board (``GrainDir``), tone per piece (``PlankTone``).&quot;&quot;&quot;</span>
+    mat = bpy.data.materials.new(name)
+    mat.use_nodes = <span class="k">True</span>
+    nt = mat.node_tree
+    bsdf = nt.nodes[<span class="s">&quot;Principled BSDF&quot;</span>]
+    coord = nt.nodes.new(<span class="s">&quot;ShaderNodeTexCoord&quot;</span>)
+    gdir = nt.nodes.new(<span class="s">&quot;ShaderNodeAttribute&quot;</span>)
+    gdir.attribute_name = <span class="s">&quot;GrainDir&quot;</span>
+    tone = nt.nodes.new(<span class="s">&quot;ShaderNodeAttribute&quot;</span>)
+    tone.attribute_name = <span class="s">&quot;PlankTone&quot;</span>
+    dot = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    dot.operation = <span class="s">&quot;DOT_PRODUCT&quot;</span>
+    nt.links.new(coord.outputs[<span class="s">&quot;Object&quot;</span>], dot.inputs[<span class="n">0</span>])
+    nt.links.new(gdir.outputs[<span class="s">&quot;Vector&quot;</span>], dot.inputs[<span class="n">1</span>])
+    squash = nt.nodes.new(<span class="s">&quot;ShaderNodeMath&quot;</span>)
+    squash.operation = <span class="s">&quot;MULTIPLY&quot;</span>
+    squash.inputs[<span class="n">1</span>].default_value = <span class="n">0.94</span>
+    nt.links.new(dot.outputs[<span class="s">&quot;Value&quot;</span>], squash.inputs[<span class="n">0</span>])
+    along = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    along.operation = <span class="s">&quot;SCALE&quot;</span>
+    nt.links.new(gdir.outputs[<span class="s">&quot;Vector&quot;</span>], along.inputs[<span class="n">0</span>])
+    nt.links.new(squash.outputs[<span class="s">&quot;Value&quot;</span>], along.inputs[<span class="s">&quot;Scale&quot;</span>])
+    grain_co = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    grain_co.operation = <span class="s">&quot;SUBTRACT&quot;</span>
+    nt.links.new(coord.outputs[<span class="s">&quot;Object&quot;</span>], grain_co.inputs[<span class="n">0</span>])
+    nt.links.new(along.outputs[<span class="s">&quot;Vector&quot;</span>], grain_co.inputs[<span class="n">1</span>])
+    shift = nt.nodes.new(<span class="s">&quot;ShaderNodeVectorMath&quot;</span>)
+    shift.operation = <span class="s">&quot;ADD&quot;</span>
+    nt.links.new(grain_co.outputs[<span class="s">&quot;Vector&quot;</span>], shift.inputs[<span class="n">0</span>])
+    nt.links.new(tone.outputs[<span class="s">&quot;Fac&quot;</span>], shift.inputs[<span class="n">1</span>])
+    noise = nt.nodes.new(<span class="s">&quot;ShaderNodeTexNoise&quot;</span>)
+    noise.inputs[<span class="s">&quot;Scale&quot;</span>].default_value = WOOD_GRAIN_SCALE
+    noise.inputs[<span class="s">&quot;Detail&quot;</span>].default_value = <span class="n">6.0</span>
+    noise.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.62</span>
+    nt.links.new(shift.outputs[<span class="s">&quot;Vector&quot;</span>], noise.inputs[<span class="s">&quot;Vector&quot;</span>])
+    ramp = nt.nodes.new(<span class="s">&quot;ShaderNodeValToRGB&quot;</span>)
+    ramp.color_ramp.elements[<span class="n">0</span>].position = <span class="n">0.30</span>
+    ramp.color_ramp.elements[<span class="n">0</span>].color = (<span class="n">0.12</span>, <span class="n">0.052</span>, <span class="n">0.018</span>, <span class="n">1.0</span>)
+    ramp.color_ramp.elements[<span class="n">1</span>].position = <span class="n">0.72</span>
+    ramp.color_ramp.elements[<span class="n">1</span>].color = (<span class="n">0.38</span>, <span class="n">0.18</span>, <span class="n">0.065</span>, <span class="n">1.0</span>)
+    nt.links.new(noise.outputs[<span class="s">&quot;Fac&quot;</span>], ramp.inputs[<span class="s">&quot;Fac&quot;</span>])
+    gain = nt.nodes.new(<span class="s">&quot;ShaderNodeMath&quot;</span>)
+    gain.operation = <span class="s">&quot;MULTIPLY_ADD&quot;</span>
+    gain.inputs[<span class="n">1</span>].default_value = <span class="n">1.1</span>
+    gain.inputs[<span class="n">2</span>].default_value = <span class="n">0.45</span>
+    nt.links.new(tone.outputs[<span class="s">&quot;Fac&quot;</span>], gain.inputs[<span class="n">0</span>])
+    mix = nt.nodes.new(<span class="s">&quot;ShaderNodeMix&quot;</span>)
+    mix.data_type = <span class="s">&quot;RGBA&quot;</span>
+    mix.blend_type = <span class="s">&quot;MULTIPLY&quot;</span>
+    _sock(mix.inputs, <span class="s">&quot;Factor_Float&quot;</span>).default_value = <span class="n">1.0</span>
+    nt.links.new(ramp.outputs[<span class="s">&quot;Color&quot;</span>], _sock(mix.inputs, <span class="s">&quot;A_Color&quot;</span>))
+    nt.links.new(gain.outputs[<span class="s">&quot;Value&quot;</span>], _sock(mix.inputs, <span class="s">&quot;B_Color&quot;</span>))
+    nt.links.new(_sock(mix.outputs, <span class="s">&quot;Result_Color&quot;</span>), bsdf.inputs[<span class="s">&quot;Base Color&quot;</span>])
+    rough = nt.nodes.new(<span class="s">&quot;ShaderNodeMapRange&quot;</span>)
+    rough.inputs[<span class="s">&quot;To Min&quot;</span>].default_value = <span class="n">0.72</span>
+    rough.inputs[<span class="s">&quot;To Max&quot;</span>].default_value = <span class="n">0.52</span>
+    nt.links.new(noise.outputs[<span class="s">&quot;Fac&quot;</span>], rough.inputs[<span class="s">&quot;Value&quot;</span>])
+    nt.links.new(rough.outputs[<span class="s">&quot;Result&quot;</span>], bsdf.inputs[<span class="s">&quot;Roughness&quot;</span>])
+    <span class="k">return</span> mat
+
+
+<span class="k">def</span> clip_x(ring, x, keep_above):
+    <span class="s">&quot;&quot;&quot;Sutherland-Hodgman clip of a closed xy ring against the line X = x.&quot;&quot;&quot;</span>
+    out = []
+    n = len(ring)
+    <span class="k">for</span> i <span class="k">in</span> range(n):
+        p, q = ring[i], ring[(i + <span class="n">1</span>) % n]
+        p_in = p[<span class="n">0</span>] &gt;= x <span class="k">if</span> keep_above <span class="k">else</span> p[<span class="n">0</span>] &lt;= x
+        q_in = q[<span class="n">0</span>] &gt;= x <span class="k">if</span> keep_above <span class="k">else</span> q[<span class="n">0</span>] &lt;= x
+        <span class="k">if</span> p_in:
+            out.append(p)
+        <span class="k">if</span> p_in != q_in:
+            t = (x - p[<span class="n">0</span>]) / (q[<span class="n">0</span>] - p[<span class="n">0</span>])
+            out.append((x, p[<span class="n">1</span>] + t * (q[<span class="n">1</span>] - p[<span class="n">1</span>])))
+    <span class="c"># a cut landing on an existing vertex would leave a zero-length edge</span>
+    clean = []
+    <span class="k">for</span> p <span class="k">in</span> out:
+        <span class="k">if</span> <span class="k">not</span> clean <span class="k">or</span> math.dist(p, clean[-<span class="n">1</span>]) &gt; <span class="n">1e-4</span>:
+            clean.append(p)
+    <span class="k">if</span> len(clean) &gt; <span class="n">2</span> <span class="k">and</span> math.dist(clean[<span class="n">0</span>], clean[-<span class="n">1</span>]) &lt;= <span class="n">1e-4</span>:
+        clean.pop()
+    <span class="k">return</span> clean
+
+
+<span class="k">def</span> add_board_disk(bm, z0, z1, xy_ring, mat_idx, n_boards):
+    <span class="s">&quot;&quot;&quot;A disk of ``n_boards`` boards, the outline cut across X with seams between.
+
+    Each board is the croze outline clipped to its strip, so the outer
+    edge of every board is still the croze and the bottom seats exactly
+    as the one-piece disk did.
+    &quot;&quot;&quot;</span>
+    xs = [p[<span class="n">0</span>] <span class="k">for</span> p <span class="k">in</span> xy_ring]
+    x_lo, x_hi = min(xs), max(xs)
+    w = (x_hi - x_lo) / n_boards
+    <span class="k">for</span> k <span class="k">in</span> range(n_boards):
+        ring = xy_ring
+        <span class="k">if</span> k &gt; <span class="n">0</span>:
+            ring = clip_x(ring, x_lo + k * w + BOARD_SEAM * <span class="n">0.5</span>, <span class="k">True</span>)
+        <span class="k">if</span> k &lt; n_boards - <span class="n">1</span>:
+            ring = clip_x(ring, x_lo + (k + <span class="n">1</span>) * w - BOARD_SEAM * <span class="n">0.5</span>, <span class="k">False</span>)
+        add_polygon_disk(bm, z0, z1, ring, mat_idx)
+
+
+<span class="k">def</span> board_audit(me, z_lo, z_hi):
+    <span class="s">&quot;&quot;&quot;Boards of the flat wooden disk between ``z_lo`` and ``z_hi``: count and seams.
+
+    A board is a thin wooden shell wide in plan. Sorted across X, the
+    seam is the gap between one board&#x27;s max X and the next one&#x27;s min X.
+    &quot;&quot;&quot;</span>
+    boards = []
+    <span class="k">for</span> g <span class="k">in</span> shells(me):
+        <span class="k">if</span> mat_of(me, g) != WOOD_IDX:
+            <span class="k">continue</span>
+        a = shell_aabb(me, g)
+        <span class="k">if</span> a[<span class="n">5</span>] - a[<span class="n">2</span>] &gt; <span class="n">0.06</span> <span class="k">or</span> max(a[<span class="n">3</span>] - a[<span class="n">0</span>], a[<span class="n">4</span>] - a[<span class="n">1</span>]) &lt; BOARD_MIN_SPAN:
+            <span class="k">continue</span>
+        <span class="k">if</span> <span class="k">not</span> (z_lo &lt;= <span class="n">0.5</span> * (a[<span class="n">2</span>] + a[<span class="n">5</span>]) &lt;= z_hi):
+            <span class="k">continue</span>
+        boards.append(a)
+    boards.sort(key=<span class="k">lambda</span> a: a[<span class="n">0</span>])
+    seams = [boards[i + <span class="n">1</span>][<span class="n">0</span>] - boards[i][<span class="n">3</span>] <span class="k">for</span> i <span class="k">in</span> range(len(boards) - <span class="n">1</span>)]
+    <span class="k">return</span> len(boards), seams
+
+
+<span class="k">def</span> bucket_materials():
+    <span class="s">&quot;&quot;&quot;(wood, iron, rope): shared by the check, the render and inspection.&quot;&quot;&quot;</span>
+    wood = wood_material(<span class="s">&quot;BucketWood&quot;</span>)
+    metal = principled(
+        <span class="s">&quot;BucketHoop&quot;</span>, (<span class="n">0.17</span>, <span class="n">0.165</span>, <span class="n">0.155</span>, <span class="n">1.0</span>), <span class="n">0.80</span>, <span class="n">0.46</span>,
+        noise_scale=<span class="n">18.0</span>, wear=(<span class="n">0.20</span>, <span class="n">0.085</span>, <span class="n">0.032</span>, <span class="n">1.0</span>),
+    )
+    rope = principled(
+        <span class="s">&quot;BucketRope&quot;</span>, (<span class="n">0.50</span>, <span class="n">0.40</span>, <span class="n">0.24</span>, <span class="n">1.0</span>), <span class="n">0.0</span>, <span class="n">0.80</span>,
+        noise_scale=<span class="n">60.0</span>, wear=(<span class="n">0.30</span>, <span class="n">0.22</span>, <span class="n">0.12</span>, <span class="n">1.0</span>),
+    )
+    <span class="k">return</span> wood, metal, rope
+
+
+<span class="k">def</span> rope_through_plates(me):
+    <span class="s">&quot;&quot;&quot;Rope vertices inside an ear plate&#x27;s box: the rope must pass the plates.
+
+    The ear plates are the two eight-vertex iron shells high on the
+    bucket. A rope vertex strictly inside either box is rope running
+    through iron.
+    &quot;&quot;&quot;</span>
+    plates, rope = [], []
+    <span class="k">for</span> g <span class="k">in</span> shells(me):
+        mat = mat_of(me, g)
+        <span class="k">if</span> mat == METAL_IDX <span class="k">and</span> len(g) == <span class="n">8</span> <span class="k">and</span> shell_aabb(me, g)[<span class="n">2</span>] &gt; <span class="n">0.25</span>:
+            plates.append(shell_aabb(me, g))
+        <span class="k">elif</span> mat == ROPE_IDX:
+            rope.extend(g)
+    eps = <span class="n">1e-5</span>
+    inside = <span class="n">0</span>
+    <span class="k">for</span> i <span class="k">in</span> rope:
+        p = me.vertices[i].co
+        <span class="k">for</span> a <span class="k">in</span> plates:
+            <span class="k">if</span> (a[<span class="n">0</span>] + eps &lt; p.x &lt; a[<span class="n">3</span>] - eps <span class="k">and</span> a[<span class="n">1</span>] + eps &lt; p.y &lt; a[<span class="n">4</span>] - eps
+                    <span class="k">and</span> a[<span class="n">2</span>] + eps &lt; p.z &lt; a[<span class="n">5</span>] - eps):
+                inside += <span class="n">1</span>
+                <span class="k">break</span>
+    <span class="k">return</span> len(plates), inside
+
+
 <span class="k">def</span> body_plan(me):
     groups = shells(me)
     xs, ys, z0s, z1s = [], [], [], []
@@ -1283,6 +1541,8 @@ <h2>Source</h2>
     float_handle=<span class="k">False</span>,
     round_band=<span class="k">False</span>,
     float_bottom=<span class="k">False</span>,
+    one_piece_bottom=<span class="k">False</span>,
+    sunk_rope=<span class="k">False</span>,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=<span class="k">True</span>)
     flags = dict(
@@ -1290,21 +1550,14 @@ <h2>Source</h2>
         float_handle=float_handle,
         round_band=round_band,
         float_bottom=float_bottom,
+        one_piece_bottom=one_piece_bottom,
+        sunk_rope=sunk_rope,
     )
     low = build_bucket_mesh(<span class="s">&quot;BucketLow&quot;</span>, <span class="n">0.003</span>, <span class="n">2</span>, **flags)
     high = build_bucket_mesh(<span class="s">&quot;BucketHigh&quot;</span>, <span class="n">0.003</span>, <span class="n">4</span>, **flags)
-    wood = principled(
-        <span class="s">&quot;BucketWood&quot;</span>, (<span class="n">0.46</span>, <span class="n">0.24</span>, <span class="n">0.09</span>, <span class="n">1.0</span>), <span class="n">0.0</span>, <span class="n">0.52</span>,
-        noise_scale=<span class="n">7.0</span>, wear=(<span class="n">0.28</span>, <span class="n">0.14</span>, <span class="n">0.05</span>, <span class="n">1.0</span>),
-    )
-    metal = principled(
-        <span class="s">&quot;BucketHoop&quot;</span>, (<span class="n">0.55</span>, <span class="n">0.53</span>, <span class="n">0.50</span>, <span class="n">1.0</span>), <span class="n">1.0</span>, <span class="n">0.28</span>,
-        noise_scale=<span class="n">5.0</span>, wear=(<span class="n">0.35</span>, <span class="n">0.32</span>, <span class="n">0.28</span>, <span class="n">1.0</span>),
-    )
-    rope = principled(
-        <span class="s">&quot;BucketRope&quot;</span>, (<span class="n">0.42</span>, <span class="n">0.32</span>, <span class="n">0.18</span>, <span class="n">1.0</span>), <span class="n">0.0</span>, <span class="n">0.72</span>,
-        noise_scale=<span class="n">9.0</span>, wear=(<span class="n">0.30</span>, <span class="n">0.22</span>, <span class="n">0.12</span>, <span class="n">1.0</span>),
-    )
+    wood, metal, rope = bucket_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal, rope)
     assign_slots(high, wood, metal, rope)
     <span class="k">if</span> stray_vert:
@@ -1338,6 +1591,8 @@ <h2>Source</h2>
     bite_min, bite_max = hoop_seat(low.data, spans)
     bjoin = bail_join(low.data)
     fgap = floor_gap(low.data)
+    n_boards, seams = board_audit(low.data, <span class="n">0.0</span>, <span class="n">0.1</span>)
+    n_plates, rope_in_plate = rope_through_plates(low.data)
     dia, ht = body_plan(low.data)
     print(
         <span class="s">f&quot;</span><span class="s">measured hygiene loose_v=</span>{hyg[<span class="s">&#x27;loose_v&#x27;</span>]}<span class="s"> loose_e=</span>{hyg[<span class="s">&#x27;loose_e&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
@@ -1349,6 +1604,11 @@ <h2>Source</h2>
         <span class="s">f&quot;</span><span class="s">hoop_bite=</span>{bite_min:<span class="s">.5f</span>}<span class="s">..</span>{bite_max:<span class="s">.5f</span>}<span class="s"> bail_join=</span>{bjoin:<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
         <span class="s">f&quot;</span><span class="s">floor_gap=</span>{fgap:<span class="s">.5f</span>}<span class="s"> body=</span>{dia:<span class="s">.4f</span>}<span class="s">x</span>{ht:<span class="s">.4f</span>}<span class="s">&quot;</span>
     )
+    print(
+        <span class="s">f&quot;</span><span class="s">measured bottom_boards=</span>{n_boards}<span class="s"> </span><span class="s">&quot;</span>
+        <span class="s">f&quot;</span><span class="s">seams=</span>{min(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s">..</span>{max(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
+        <span class="s">f&quot;</span><span class="s">ear_plates=</span>{n_plates}<span class="s"> rope_in_plate=</span>{rope_in_plate}<span class="s">&quot;</span>
+    )
 
     img, tex = setup_bake_image(low, wood)
     <span class="k">if</span> img <span class="k">is</span> <span class="k">None</span>:
@@ -1376,6 +1636,10 @@ <h2>Source</h2>
         os.remove(export_path)
     export_unity(export_path, [low, collider])
     export_size = os.path.getsize(export_path) <span class="k">if</span> os.path.isfile(export_path) <span class="k">else</span> <span class="n">0</span>
+    <span class="c"># Blender points TMPDIR at the working directory, so the export must not</span>
+    <span class="c"># outlive the measurement.</span>
+    <span class="k">if</span> os.path.exists(export_path):
+        os.remove(export_path)
 
     print(<span class="s">f&quot;</span><span class="s">blender=</span>{tuple(bpy.app.version)}<span class="s"> skip_decimate=</span>{skip_decimate}<span class="s">&quot;</span>)
     print(
@@ -1503,6 +1767,24 @@ <h2>Source</h2>
             <span class="s">&quot;(--float-bottom is the designed fail)&quot;</span>,
             <span class="n">17</span>,
         ), <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>
+    <span class="k">if</span> (
+        n_boards != BOTTOM_BOARDS
+        <span class="k">or</span> min(seams, default=<span class="n">0.0</span>) &lt; BOARD_SEAM_MIN
+        <span class="k">or</span> max(seams, default=<span class="n">99.0</span>) &gt; BOARD_SEAM_MAX
+    ):
+        <span class="k">return</span> fail(
+            <span class="s">f&quot;</span><span class="s">bottom boards </span>{n_boards}<span class="s"> != </span>{BOTTOM_BOARDS}<span class="s">, or seams </span><span class="s">&quot;</span>
+            <span class="s">f&quot;</span>{min(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s">..</span>{max(seams, default=<span class="n">0.0</span>):<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
+            <span class="s">f&quot;</span><span class="s">outside [</span>{BOARD_SEAM_MIN}<span class="s">, </span>{BOARD_SEAM_MAX}<span class="s">] </span><span class="s">&quot;</span>
+            <span class="s">&quot;(--one-piece-bottom is the designed fail)&quot;</span>,
+            <span class="n">17</span>,
+        ), <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>
+    <span class="k">if</span> n_plates != <span class="n">2</span> <span class="k">or</span> rope_in_plate:
+        <span class="k">return</span> fail(
+            <span class="s">f&quot;</span><span class="s">ear plates </span>{n_plates}<span class="s"> != 2, or </span>{rope_in_plate}<span class="s"> rope vertices </span><span class="s">&quot;</span>
+            <span class="s">&quot;inside a plate (--sunk-rope is the designed fail)&quot;</span>,
+            <span class="n">17</span>,
+        ), <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>, <span class="k">None</span>
     <span class="k">if</span> bite_min &lt; HOOP_BITE_MIN <span class="k">or</span> bite_max &gt; HOOP_BITE_MAX:
         <span class="k">return</span> fail(
             <span class="s">f&quot;</span><span class="s">hoop bite </span>{bite_min:<span class="s">.5f</span>}<span class="s">..</span>{bite_max:<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
@@ -1634,6 +1916,8 @@ <h2>Source</h2>
     p.add_argument(<span class="s">&quot;--float-handle&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     p.add_argument(<span class="s">&quot;--float-bottom&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     p.add_argument(<span class="s">&quot;--round-band&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
+    p.add_argument(<span class="s">&quot;--one-piece-bottom&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
+    p.add_argument(<span class="s">&quot;--sunk-rope&quot;</span>, action=<span class="s">&quot;store_true&quot;</span>)
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1644,6 +1928,8 @@ <h2>Source</h2>
         float_handle=args.float_handle,
         round_band=args.round_band,
         float_bottom=args.float_bottom,
+        one_piece_bottom=args.one_piece_bottom,
+        sunk_rope=args.sunk_rope,
     )
     <span class="k">if</span> code:
         <span class="k">return</span> code
@@ -1668,7 +1954,7 @@ <h2>Source</h2>
   </main>
   <dialog class="lightbox" id="lightbox" aria-label="Full-size render">
     <button class="lightbox-close" type="button" autofocus>Close</button>
-    <img src="../assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with metal hoops and a curved wooden bail handle." />
+    <img src="../assets/wooden-bucket-hero.webp" alt="A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/examples/color-attribute-wheel/README.md b/examples/color-attribute-wheel/README.md
index b5161458..79409971 100644
--- a/examples/color-attribute-wheel/README.md
+++ b/examples/color-attribute-wheel/README.md
@@ -19,6 +19,16 @@ match the closed-form HSV value for the vertex they reference. A separate check
 in the render path confirms the `Attribute` node is actually linked to Base
 Color, not just present in the node tree.
 
+## Staging
+
+The disc is zero-thickness, and the still used to show it as a paper-thin oval
+hovering 8 cm above the floor. The render path now gives it a render-only
+Solidify body (5 cm) and stands it at the same 52° lean on a dark plinth, with
+a strut behind it, easel-style. The height is computed so the lowest point of
+the rim rests on the plinth. The mesh `check()` asserts is unchanged: the
+modifier is added after the check and only in the render path. Measured
+framing on 5.2.1: fill 0.794 y, every margin ≥ 0.094.
+
 ## Run
 
 ```bash
diff --git a/examples/color-attribute-wheel/color_attribute_wheel.py b/examples/color-attribute-wheel/color_attribute_wheel.py
index 86e01aac..6416e972 100644
--- a/examples/color-attribute-wheel/color_attribute_wheel.py
+++ b/examples/color-attribute-wheel/color_attribute_wheel.py
@@ -23,6 +23,7 @@
 """
 import bpy, bmesh, sys, os, math, colorsys, argparse
 from array import array
+from mathutils import Vector
 
 RINGS = 14
 SEGMENTS = 72
@@ -197,8 +198,54 @@ def render_still(obj, path, engine):
     # stand the disc up toward the camera like an easel: the wheel is the
     # subject, so it should present nearly face-on and fill the frame instead
     # of lying foreshortened on the floor.
-    obj.location = (0.0, 0.0, 1.34)
-    obj.rotation_euler = (math.radians(52), 0.0, math.radians(10))
+    # render-only: a Solidify body so the disc reads as a painted board, not
+    # a zero-thickness sheet, resting on a dark plinth and propped from
+    # behind by a strut, easel-style, instead of hovering above the floor.
+    disc_t = 0.05
+    plinth_h = 0.12
+    tilt = math.radians(52)
+    solid = obj.modifiers.new("Board", 'SOLIDIFY')
+    solid.thickness = disc_t
+    solid.offset = -1.0
+    # lowest rim point sits R_OUTER * sin(tilt) below the centre, and the
+    # board's back face another disc_t * cos(tilt) below that
+    obj.location = (0.0, 0.0, plinth_h + R_OUTER * math.sin(tilt) + disc_t * math.cos(tilt))
+    obj.rotation_euler = (tilt, 0.0, math.radians(10))
+
+    stand_mat = bpy.data.materials.new("Stand")
+    stand_mat.use_nodes = True
+    sb = stand_mat.node_tree.nodes["Principled BSDF"]
+    sb.inputs["Base Color"].default_value = (0.012, 0.012, 0.014, 1.0)
+    sb.inputs["Roughness"].default_value = 0.45
+
+    def stand_part(name, build):
+        me = bpy.data.meshes.new(name)
+        bm = bmesh.new()
+        try:
+            build(bm)
+            bm.to_mesh(me)
+        finally:
+            bm.free()
+        me.materials.append(stand_mat)
+        ob = bpy.data.objects.new(name, me)
+        scene.collection.objects.link(ob)
+        return ob
+
+    bpy.context.view_layer.update()
+    mw = obj.matrix_world
+    rim_low = mw @ Vector((0.0, -R_OUTER, 0.0))
+    plinth = stand_part("Plinth", lambda bm: bmesh.ops.create_cube(bm, size=1.0))
+    plinth.scale = (1.5, 0.9, plinth_h)
+    plinth.location = (rim_low.x, rim_low.y + 0.25, plinth_h / 2.0)
+    plinth.rotation_euler = (0.0, 0.0, math.radians(10))
+    # the strut runs from the board's back, above centre, down to the plinth
+    top = mw @ Vector((0.0, 0.45, -disc_t))
+    foot = Vector((top.x, top.y + 0.95, plinth_h))
+    span = top - foot
+    strut = stand_part("Strut", lambda bm: bmesh.ops.create_cone(
+        bm, cap_ends=True, segments=16, radius1=0.035, radius2=0.035, depth=span.length))
+    strut.location = (top + foot) / 2.0
+    strut.rotation_euler = Vector((0.0, 0.0, 1.0)).rotation_difference(span).to_euler()
 
     floor_me = bpy.data.meshes.new("Floor")
     bm = bmesh.new()
@@ -247,13 +294,13 @@ def light(name, loc, energy, size, col, rot):
     light("Wedge", (2.0, 5.2, 3.6), 220.0, 6.0, (1.0, 0.76, 0.5), (-68, 0, 190))
 
     aim = bpy.data.objects.new("Aim", None)
-    aim.location = obj.location
+    aim.location = obj.location - Vector((0.0, 0.0, 0.2))
     scene.collection.objects.link(aim)
 
     cam_data = bpy.data.cameras.new("Cam")
     cam_data.lens = 50.0
     cam = bpy.data.objects.new("Cam", cam_data)
-    cam.location = (0.0, -8.0, 2.4)
+    cam.location = (0.0, -9.4, 2.5)
     con = cam.constraints.new('TRACK_TO')
     con.target = aim
     con.track_axis = 'TRACK_NEGATIVE_Z'
diff --git a/examples/color-attribute-wheel/preview.webp b/examples/color-attribute-wheel/preview.webp
index 28771901..bd269443 100644
Binary files a/examples/color-attribute-wheel/preview.webp and b/examples/color-attribute-wheel/preview.webp differ
diff --git a/examples/gallery.json b/examples/gallery.json
index 4d043d9a..f59c399d 100644
--- a/examples/gallery.json
+++ b/examples/gallery.json
@@ -60,7 +60,7 @@
       "name": "wave-displace",
       "dir": "examples/wave-displace",
       "teaches": "Bulk vertex IO at real scale — 9,409 vertices displaced into a standing wave with one foreach_get and one foreach_set, no per-vertex access.",
-      "alt": "A blue grid surface displaced into rolling sine-wave hills.",
+      "alt": "A blue tile whose top is a grid displaced into rolling sine-wave hills, standing on a dark studio floor.",
       "witnessesFix": "The bulk path is correct, not just fast: the Z span matches the wave amplitude and every vertex matches the closed-form wave, so a stride bug in the flat buffer cannot hide.",
       "hero": "docs/gallery/assets/wave-displace-hero.webp",
       "preview": "examples/wave-displace/preview.webp",
@@ -205,7 +205,7 @@
       "name": "color-attribute-wheel",
       "dir": "examples/color-attribute-wheel",
       "teaches": "The modern color-attributes API — mesh.color_attributes.new() on the CORNER domain, filled by expanding per-vertex HSV across face corners with foreach_get/foreach_set, then wired into a shader Attribute node.",
-      "alt": "A disc painted with a full hue wheel that fades to white at the centre.",
+      "alt": "A board painted with a full hue wheel that fades to white at the centre, leaning on a dark plinth.",
       "witnessesFix": "CORNER-domain attributes are sized to loop count, not vertex count; the check asserts the sizing, that active_color points at it, and that the Attribute node is actually linked to Base Color, not just present.",
       "hero": "docs/gallery/assets/color-attribute-wheel-hero.webp",
       "preview": "examples/color-attribute-wheel/preview.webp",
diff --git a/examples/wave-displace/README.md b/examples/wave-displace/README.md
index d984e025..ab4e94b3 100644
--- a/examples/wave-displace/README.md
+++ b/examples/wave-displace/README.md
@@ -11,13 +11,19 @@ the flat grid gained the expected Z span (the write actually landed) and that **
 vertex matches the closed-form wave, so a stride or interleave bug in the flat buffer
 cannot hide behind a lucky probe.
 
-## Framing deviation
-
-Edge-to-edge field — the displaced sheet fills the frame and crops at the left,
-right, and bottom edges so the wave reads as a surface, not an object on a
-stage (measured fill 1.000x/0.817y with edge touch on three sides). If wired
-to `examples/gallery_framing.py`, call it with
-`deviation="edge-to-edge wave field; the fill is the point"`.
+## Staging
+
+The still used to be an edge-to-edge field: the sheet cropped at the left,
+right and bottom edges on a black void, so nothing showed where the surface
+ended or what it stood on. `gallery_framing` has no `deviation=` flag any more,
+so that framing could not be gated at all.
+
+The render path now stages a **copy** of the checked grid. Its boundary is
+extruded straight down to a flat base 0.30 m below the deepest trough, so the
+wave is the top face of a cast tile standing on the studio floor, framed whole.
+The checked `Wave` object is left exactly as asserted and hidden from the
+render. The copy is render-only and never enters `check()`. Measured framing on
+5.2.1: fill 0.753 x / 0.761 y, every margin ≥ 0.117.
 
 ## Run
 
diff --git a/examples/wave-displace/preview.webp b/examples/wave-displace/preview.webp
index 60750a36..b23d5090 100644
Binary files a/examples/wave-displace/preview.webp and b/examples/wave-displace/preview.webp differ
diff --git a/examples/wave-displace/wave_displace.py b/examples/wave-displace/wave_displace.py
index 86021208..08736e81 100644
--- a/examples/wave-displace/wave_displace.py
+++ b/examples/wave-displace/wave_displace.py
@@ -86,31 +86,87 @@ def render_still(obj, path, engine):
     bsdf.inputs["Roughness"].default_value = 0.18
     obj.data.materials.append(mat)
 
+    # render-only staging: the displaced grid is the contract and stays as
+    # checked. A copy of it gets a skirt, its boundary extruded straight
+    # down to a flat base, so the wave reads as the top of a cast tile
+    # standing on the studio floor instead of a sheet bleeding off the frame.
+    base = 0.30  # base sits this far below the deepest trough
+    tile_me = obj.data.copy()
+    bm = bmesh.new()
+    try:
+        bm.from_mesh(tile_me)
+        rim = [e for e in bm.edges if e.is_boundary]
+        ret = bmesh.ops.extrude_edge_only(bm, edges=rim)
+        skirt = [g for g in ret["geom"] if isinstance(g, bmesh.types.BMFace)]
+        for g in ret["geom"]:
+            if isinstance(g, bmesh.types.BMVert):
+                g.co.z = -AMP - base
+        bottom = [g for g in ret["geom"] if isinstance(g, bmesh.types.BMEdge) and g.is_boundary]
+        bmesh.ops.holes_fill(bm, edges=bottom, sides=0)
+        bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
+        for f in skirt:
+            f.smooth = False
+        bm.to_mesh(tile_me)
+    finally:
+        bm.free()
+    tile = bpy.data.objects.new("WaveTile", tile_me)
+    tile.location.z = AMP + base
+    scene.collection.objects.link(tile)
+    obj.hide_render = True
+
+    floor_me = bpy.data.meshes.new("Floor")
+    bm = bmesh.new()
+    try:
+        bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=60.0)
+        bm.to_mesh(floor_me)
+    finally:
+        bm.free()
+    fmat = bpy.data.materials.new("Studio")
+    fmat.use_nodes = True
+    fb = fmat.node_tree.nodes["Principled BSDF"]
+    fb.inputs["Base Color"].default_value = (0.03, 0.032, 0.037, 1.0)
+    fb.inputs["Roughness"].default_value = 0.7
+    floor_me.materials.append(fmat)
+    floor = bpy.data.objects.new("Floor", floor_me)
+    scene.collection.objects.link(floor)
+    wall = bpy.data.objects.new("Wall", floor_me.copy())
+    wall.location = (0.0, 14.0, 0.0)
+    wall.rotation_euler = (math.radians(90), 0.0, 0.0)
+    scene.collection.objects.link(wall)
+
     world = bpy.data.worlds.new("World")
     world.use_nodes = True
-    world.node_tree.nodes["Background"].inputs["Color"].default_value = (0.008, 0.009, 0.012, 1.0)
+    world.node_tree.nodes["Background"].inputs["Color"].default_value = (0.02, 0.021, 0.025, 1.0)
     scene.world = world
 
-    # grazing cool key picks out the crests; warm rim from behind
-    key = bpy.data.lights.new("Key", 'AREA'); key.energy = 2000.0; key.size = 6.0
-    key.color = (0.9, 0.95, 1.0)
-    key_ob = bpy.data.objects.new("Key", key)
-    key_ob.location = (-6.5, -5.0, 3.2)
-    key_ob.rotation_euler = (math.radians(65), 0.0, math.radians(-50))
-    scene.collection.objects.link(key_ob)
-    rim = bpy.data.lights.new("Rim", 'AREA'); rim.energy = 1300.0; rim.size = 4.0
-    rim.color = (1.0, 0.68, 0.38)
-    rim_ob = bpy.data.objects.new("Rim", rim)
-    rim_ob.location = (4.5, 6.5, 2.6)
-    rim_ob.rotation_euler = (math.radians(-68), 0.0, math.radians(148))
-    scene.collection.objects.link(rim_ob)
-
+    def light(name, loc, energy, size, col, rot):
+        ld = bpy.data.lights.new(name, 'AREA')
+        ld.energy = energy; ld.size = size; ld.color = col
+        ob = bpy.data.objects.new(name, ld)
+        ob.location = loc
+        ob.rotation_euler = tuple(math.radians(a) for a in rot)
+        scene.collection.objects.link(ob)
+
+    # grazing cool key picks out the crests; warm rim from behind; a warm
+    # wedge rakes the back wall like the rest of the gallery stages
+    light("Key", (-8.0, -7.0, 6.5), 2400.0, 7.0, (0.9, 0.95, 1.0), (55, 0, -48))
+    light("Fill", (9.0, -6.0, 3.0), 120.0, 10.0, (0.78, 0.86, 1.0), (70, 0, 55))
+    light("Rim", (5.0, 7.5, 4.0), 1800.0, 5.0, (1.0, 0.68, 0.38), (-62, 0, 148))
+    light("Wedge", (4.0, 10.5, 7.0), 1500.0, 9.0, (1.0, 0.76, 0.5), (-65, 0, 190))
+
+    aim = bpy.data.objects.new("Aim", None)
+    aim.location = (0.0, -0.4, 0.05)
+    scene.collection.objects.link(aim)
     cam_data = bpy.data.cameras.new("Cam"); cam_data.lens = 50.0
     cam = bpy.data.objects.new("Cam", cam_data)
-    cam.location = (0.0, -8.6, 4.6)
-    cam.rotation_euler = (math.radians(62), 0.0, 0.0)
+    cam.location = (7.2, -11.8, 7.4)
+    con = cam.constraints.new('TRACK_TO')
+    con.target = aim
+    con.track_axis = 'TRACK_NEGATIVE_Z'
+    con.up_axis = 'UP_Y'
     scene.collection.objects.link(cam)
     scene.camera = cam
+    scene.view_settings.view_transform = 'Standard'
 
     scene.render.engine = 'CYCLES' if engine == 'cycles' else eevee_engine_id()
     if engine == 'cycles':
diff --git a/showcase/README.md b/showcase/README.md
index 42d244a6..4721e1d9 100644
--- a/showcase/README.md
+++ b/showcase/README.md
@@ -415,6 +415,29 @@ entry in `showcase/gallery.json`, and a rendered still.
   attributes, and have the shader stretch its grain along that axis
   rather than a world axis, which a yawed member is off by its yaw.
   Nothing here is an assertion; it is found on the inspection sheet.
+  The same holds for coopered staves: `wooden-barrel` and `wooden-bucket`
+  were one flat tone until each stave got its own. Hoops are forged iron,
+  dark and rusted, not the bright polished metal both pieces first shipped
+  with.
+- **A head or bottom is boards, not a slab (exit 17).** A barrel head or
+  bucket bottom cut from one disk reads as a lid. Cut the croze outline
+  across into boards with a named seam, so every board's outer edge is
+  still the croze and the seat does not change. Assert the board count and
+  that every seam lies in a band. Classify boards by their span in plan,
+  not by a radius: a quarter of the head's width is smaller than any
+  "round" test built for the whole disk. `--one-piece-head` /
+  `--one-piece-bottom` are the falsifiers.
+- **Rope is laid, not piped.** A smooth tube with a rope material is a
+  plastic hose. Loft a three-lobed section and turn it one vertex step per
+  ring, so each lobe winds along the path as a strand. That costs the same
+  triangles as a round section of the same count. Fix the section's frame
+  to the path's plane, or the lay jumps where the path turns vertical.
+- **What passes through a part must clear its mount (exit 17).** A bail
+  through an ear ring has to clear the plate the ring hangs on. Ring
+  offsets sized to the ring (`RING_MAJOR * 0.25`) put the rope's axis 3 mm
+  off the plate and its body through it. Size the offset from the thing
+  passing through, and assert that no vertex of it lies inside the mount.
+  `--sunk-rope` restores the old offset.
 - **A section that carries the read is a budget (exit 19).** Where a
   cross-section is what makes a part recognisable — an axe handle is
   oval, a broom handle is round — assert it as a ratio band at a named
diff --git a/showcase/gallery.json b/showcase/gallery.json
index 8abe35bd..07ed49d1 100644
--- a/showcase/gallery.json
+++ b/showcase/gallery.json
@@ -35,9 +35,9 @@
     {
       "name": "wooden-barrel",
       "dir": "showcase/wooden-barrel",
-      "teaches": "A procedural wine-cask with croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "alt": "A wooden stave barrel bound by three metal hoops.",
-      "witnessesFix": "Recomputed: 7216 tris, two materials with 2512 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget.",
+      "teaches": "A procedural wine-cask with boarded, croze-seated heads and chord-lofted hoops through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
+      "alt": "A wooden stave barrel bound by four iron hoops, its head made of boards.",
+      "witnessesFix": "Recomputed: 7312 tris, two materials with 2584 wood and 1440 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.722×0.714×0.880 m, 20 grounded staves, hoop bite 0.003 m, head-croze gap 0.007 m, four boards per head with 1.5 mm seams, LOD ratios in band, convex collider 238 tris, non-empty glTF. --skip-decimate exits 9; --round-band exits 18 on the hoop-seat budget; --one-piece-head exits 17 on the head-board budget.",
       "hero": "docs/gallery/assets/wooden-barrel-hero.webp",
       "preview": "showcase/wooden-barrel/preview.webp",
       "tags": [
@@ -272,9 +272,9 @@
     {
       "name": "wooden-bucket",
       "dir": "showcase/wooden-bucket",
-      "teaches": "A procedural coopered pail with a croze-seated floor, chord-lofted hoops, and a round bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "alt": "A wooden stave bucket with metal hoops and a curved wooden bail handle.",
-      "witnessesFix": "Recomputed: 4872 tris, three materials with 1424 wood, 1020 metal, and 208 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.383×0.346×0.527 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0013 m, LOD ratios in band, convex collider 302 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget.",
+      "teaches": "A procedural coopered pail with a boarded, croze-seated floor, chord-lofted hoops, and a three-strand rope bail through the ear rings through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
+      "alt": "A wooden stave bucket with three iron hoops and a twisted rope handle through iron ear rings.",
+      "witnessesFix": "Recomputed: 5458 tris, three materials with 1448 wood, 1020 metal, and 486 rope faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.396×0.346×0.534 m, 16 grounded staves, hoop bite 0.0025 m, bail-ear gap 0.0011 m, three bottom boards, no rope vertex inside an ear plate, LOD ratios in band, convex collider 276 tris, non-empty glTF. --skip-decimate exits 9; --float-handle exits 17 on the bail-ear budget; --sunk-rope exits 17 on the rope-clearance budget.",
       "hero": "docs/gallery/assets/wooden-bucket-hero.webp",
       "preview": "showcase/wooden-bucket/preview.webp",
       "tags": [
diff --git a/showcase/wooden-barrel/README.md b/showcase/wooden-barrel/README.md
index f0201e3b..95afcdfe 100644
--- a/showcase/wooden-barrel/README.md
+++ b/showcase/wooden-barrel/README.md
@@ -1,8 +1,8 @@
 # Wooden barrel
 
 A showcase piece, not an example. Procedural wine-cask (20 staves with
-seeded width jitter, heads seated in a croze below a chime, iron hoops
-lofted on the stave faces, a bung) then the shipped pipeline: unique-cell
+seeded width jitter, heads of four boards seated in a croze below a
+chime, iron hoops lofted on the stave faces, a bung) then the shipped pipeline: unique-cell
 UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity
 glTF export.
 
@@ -10,7 +10,9 @@ Hoops evaluate the same `host_outer_r` chord as the stave flats.
 `--round-band` is the falsifier: a circle of `radius_at(z)` instead of
 the chord, which is what made the old capped cylinder float off every
 face. Heads follow the inner stave polygon, not a circle, so they fill
-the croze instead of leaving triangular slots at every joint.
+the croze instead of leaving triangular slots at every joint. Each head
+is that outline cut across into four boards with a 1.5 mm seam, so the
+seat is unchanged and the head no longer reads as a lid.
 
 It asserts **budget conformance** of the generated result. It does not
 witness an API contract. "It rendered without error" is not a check.
@@ -28,18 +30,19 @@ materials, UVs, evaluated LOD, collider, or export file.
 
 | Axis | Declared | Measured (4.5.11 / 5.1.2 / 5.2.1) |
 | --- | --- | --- |
-| Base triangles | 6000–8500 | 7216 / 7216 / 7216 |
+| Base triangles | 6000–8500 | 7312 / 7312 / 7312 |
 | LOD1 ratio | 0.32–0.62 of base | 0.5000 / 0.5000 / 0.5000 |
-| LOD2 ratio | 0.10–0.35 of base | 0.2198 / 0.2198 / 0.2198 |
-| Materials | exactly 2 distinct; ≥400 wood, ≥200 metal faces | 2 slots; 2512 / 1440 |
+| LOD2 ratio | 0.10–0.35 of base | 0.2199 / 0.2199 / 0.2199 |
+| Materials | exactly 2 distinct; ≥400 wood, ≥200 metal faces | 2 slots; 2584 / 1440 |
 | UVs | in `0..1`, AABB overlap ≤ 1e-5 | in range, overlap 0 |
 | Outer AABB | (0.722, 0.714, 0.880) m ± 0.015 | (0.7220, 0.7142, 0.8800), zmin 0 |
 | Collider tris | ≤ 400 | 238 |
-| Export | written, size > 0 | 544140 / 544140 / 544124 bytes |
+| Export | written, size > 0 | 552456 / 552456 / 552440 bytes |
 
 Base triangles rose from **4312 to 7216** in the quality pass: 12 identical
 staves with 5 mm daylight and circular hoops became 20 jittered staves,
 8-ring bulge, chord-seated hoops, polygonal croze heads, and a bung.
+Cutting each head into four boards added 96 more (7312).
 
 DECIMATE COLLAPSE triangle counts are **not** identical across series —
 the gate is a ratio band, not an exact count. Bake pixels are
@@ -67,12 +70,13 @@ Recomputed from the generated mesh, not asserted about the script.
 
 | Axis | Declared | Measured (all three) |
 | --- | --- | --- |
-| Head-croze rim BVH gap | ≤ 0.010 m | 0.00698 |
+| Head-croze rim BVH gap | ≤ 0.010 m | 0.00710 |
+| Head boards | 4 per head; every seam 0.0008–0.003 m | 4 + 4; 0.00150 |
 | Hoop bite (host r − inner hoop r) | 0.0012–0.008 m | 0.00300 |
 
 ### Falsifiers
 
-Each violates one named budget. All six were run on 4.5.11, 5.1.2 and
+Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and
 5.2.1 and returned the same code on each.
 
 | Flag | Budget violated | Exit |
@@ -83,6 +87,16 @@ Each violates one named budget. All six were run on 4.5.11, 5.1.2 and
 | `--short-staves` | named stave supports at Z=0 | 16 |
 | `--float-head` | head-croze gap | 17 |
 | `--round-band` | hoop bite band | 18 |
+| `--one-piece-head` | head boards: 4 per head | 17 |
+
+## Surface
+
+The staves were one flat tone and the hoops bright polished steel. Each
+stave and each head board now carries a seeded `PlankTone` and a
+`GrainDir` (its own long axis) as face attributes. `wood_material`
+stretches grain along that axis, so it runs up the curved staves and
+across the head boards. The hoops are dark rusted iron, the same recipe as
+`shipping-crate`. The temp `.glb` is removed once its size is measured.
 
 ## Run
 
@@ -94,6 +108,7 @@ blender --background --python wooden_barrel.py -- --lift-z
 blender --background --python wooden_barrel.py -- --short-staves
 blender --background --python wooden_barrel.py -- --float-head
 blender --background --python wooden_barrel.py -- --round-band
+blender --background --python wooden_barrel.py -- --one-piece-head
 blender --background --python wooden_barrel.py -- --output barrel.png
 ```
 
@@ -124,6 +139,6 @@ hygiene and joint-fit family.
 | 14 | `--output` produced no file |
 | 15 | Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight |
 | 16 | Not grounded: bounding box `zmin` off 0, or a named stave floats |
-| 17 | Joint fit: head-croze gap (`--float-head`) |
+| 17 | Joint fit: head-croze gap (`--float-head`), or head boards and seams (`--one-piece-head`) |
 | 18 | Seat: hoop bite band (`--round-band`) |
 | 19 | Body diameter or height off the stated real-world size |
diff --git a/showcase/wooden-barrel/preview.webp b/showcase/wooden-barrel/preview.webp
index 39891ff0..dbb431ad 100644
Binary files a/showcase/wooden-barrel/preview.webp and b/showcase/wooden-barrel/preview.webp differ
diff --git a/showcase/wooden-barrel/wooden_barrel.py b/showcase/wooden-barrel/wooden_barrel.py
index 45ce78f5..f5837467 100644
--- a/showcase/wooden-barrel/wooden_barrel.py
+++ b/showcase/wooden-barrel/wooden_barrel.py
@@ -13,8 +13,9 @@
 They are not API-contract witnesses. Each falsifier violates one named
 budget: ``--skip-decimate`` the LOD-ratio band, ``--stray-vert`` mesh
 hygiene, ``--lift-z`` grounded zmin, ``--short-staves`` named stave
-supports, ``--float-head`` head-croze joint-fit, ``--round-band`` hoop
-seat (hoop generated on a circle instead of the stave chords).
+supports, ``--float-head`` head-croze joint-fit, ``--one-piece-head``
+head boards (one slab instead of boards), ``--round-band`` hoop seat
+(hoop generated on a circle instead of the stave chords).
 
 Fixed seed 17 for stave-width jitter. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
@@ -103,6 +104,19 @@
 WOOD_IDX = 0
 METAL_IDX = 1
 
+# Each head is HEAD_BOARDS boards cut across X from the croze outline, with
+# a BOARD_SEAM between neighbours. A board is a thin wooden shell at least
+# BOARD_MIN_SPAN wide in plan (the bung is 0.05, the narrowest board 0.36).
+HEAD_BOARDS = 4
+BOARD_SEAM = 0.0015
+BOARD_SEAM_MIN = 0.0008
+BOARD_SEAM_MAX = 0.003
+BOARD_MIN_SPAN = 0.30
+# Per-piece wood tone jitter and grain frequency, as in shipping-crate.
+PLANK_TONE_JITTER = 0.28
+TONE_SEED = 29
+WOOD_GRAIN_SCALE = 30.0
+
 
 def eevee_engine_id():
     return "BLENDER_EEVEE" if bpy.app.version >= (5, 0, 0) else "BLENDER_EEVEE_NEXT"
@@ -405,6 +419,7 @@ def build_barrel_mesh(
     short_staves=False,
     float_head=False,
     round_band=False,
+    one_piece_head=False,
 ):
     bm = bmesh.new()
     gap_ang = GAP_M / R_MID
@@ -417,15 +432,16 @@ def build_barrel_mesh(
         bot_z1 = CHIME + LID_T
         top_z0 = HEIGHT - CHIME - LID_T
         top_z1 = HEIGHT - CHIME
-        add_polygon_disk(
+        n_boards = 1 if one_piece_head else HEAD_BOARDS
+        add_board_disk(
             bm, bot_z0, bot_z1,
             croze_xy(spans, 0.5 * (bot_z0 + bot_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, n_boards,
         )
-        add_polygon_disk(
+        add_board_disk(
             bm, top_z0, top_z1,
             croze_xy(spans, 0.5 * (top_z0 + top_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, n_boards,
         )
         add_bung(bm, 0.5 * (spans[0][0] + spans[0][1]), BUNG_Z, spans)
         build_hoops(bm, spans, round_band)
@@ -663,8 +679,7 @@ def head_gap(me, spans):
             continue
         a = shell_aabb(me, g)
         dz = a[5] - a[2]
-        r = 0.25 * ((a[3] - a[0]) + (a[4] - a[1]))
-        if dz < 0.06 and r > 0.15:
+        if dz < 0.06 and max(a[3] - a[0], a[4] - a[1]) >= BOARD_MIN_SPAN:
             heads.append(g)
         elif dz > 0.50:
             staves.append(g)
@@ -701,6 +716,191 @@ def head_gap(me, spans):
         bm_s.free()
 
 
+def _long_axis(pts):
+    """Principal axis of a point set, by power iteration on its covariance."""
+    c = sum(pts, Vector()) / len(pts)
+    cov = [[0.0] * 3 for _ in range(3)]
+    for p in pts:
+        d = p - c
+        for i in range(3):
+            for j in range(3):
+                cov[i][j] += d[i] * d[j]
+    v = Vector((1.0, 0.3, 0.1))
+    for _ in range(30):
+        w = Vector([sum(cov[i][j] * v[j] for j in range(3)) for i in range(3)])
+        if w.length < 1e-12:
+            break
+        v = w.normalized()
+    return v
+
+
+def paint_planks(me):
+    """Per-shell ``PlankTone`` and ``GrainDir`` face attributes for the wood shader.
+
+    Every stave and every board is its own shell, so each gets one tone and
+    grain running along its own long axis (up the curved staves, across
+    the flat boards).
+    """
+    tone = [0.5] * len(me.polygons)
+    grain = [(0.0, 0.0, 1.0)] * len(me.polygons)
+    owner = {}
+    rng = random.Random(TONE_SEED)
+    for g in shells(me):
+        pts = [me.vertices[i].co.copy() for i in g]
+        d = _long_axis(pts) if len(pts) > 2 else Vector((0.0, 0.0, 1.0))
+        t = 0.5 + rng.uniform(-PLANK_TONE_JITTER, PLANK_TONE_JITTER)
+        for i in g:
+            owner[i] = (t, tuple(d))
+    for poly in me.polygons:
+        t, d = owner[poly.vertices[0]]
+        tone[poly.index] = t
+        grain[poly.index] = d
+    a = me.attributes.new("PlankTone", "FLOAT", "FACE")
+    a.data.foreach_set("value", tone)
+    b = me.attributes.new("GrainDir", "FLOAT_VECTOR", "FACE")
+    b.data.foreach_set("vector", [c for v in grain for c in v])
+
+
+def _sock(sockets, identifier):
+    """A Mix-node socket by identifier; its A/B/Result names repeat per type."""
+    return next(sk for sk in sockets if sk.identifier == identifier)
+
+
+def wood_material(name):
+    """Grain along each stave or board (``GrainDir``), tone per piece (``PlankTone``)."""
+    mat = bpy.data.materials.new(name)
+    mat.use_nodes = True
+    nt = mat.node_tree
+    bsdf = nt.nodes["Principled BSDF"]
+    coord = nt.nodes.new("ShaderNodeTexCoord")
+    gdir = nt.nodes.new("ShaderNodeAttribute")
+    gdir.attribute_name = "GrainDir"
+    tone = nt.nodes.new("ShaderNodeAttribute")
+    tone.attribute_name = "PlankTone"
+    dot = nt.nodes.new("ShaderNodeVectorMath")
+    dot.operation = "DOT_PRODUCT"
+    nt.links.new(coord.outputs["Object"], dot.inputs[0])
+    nt.links.new(gdir.outputs["Vector"], dot.inputs[1])
+    squash = nt.nodes.new("ShaderNodeMath")
+    squash.operation = "MULTIPLY"
+    squash.inputs[1].default_value = 0.94
+    nt.links.new(dot.outputs["Value"], squash.inputs[0])
+    along = nt.nodes.new("ShaderNodeVectorMath")
+    along.operation = "SCALE"
+    nt.links.new(gdir.outputs["Vector"], along.inputs[0])
+    nt.links.new(squash.outputs["Value"], along.inputs["Scale"])
+    grain_co = nt.nodes.new("ShaderNodeVectorMath")
+    grain_co.operation = "SUBTRACT"
+    nt.links.new(coord.outputs["Object"], grain_co.inputs[0])
+    nt.links.new(along.outputs["Vector"], grain_co.inputs[1])
+    shift = nt.nodes.new("ShaderNodeVectorMath")
+    shift.operation = "ADD"
+    nt.links.new(grain_co.outputs["Vector"], shift.inputs[0])
+    nt.links.new(tone.outputs["Fac"], shift.inputs[1])
+    noise = nt.nodes.new("ShaderNodeTexNoise")
+    noise.inputs["Scale"].default_value = WOOD_GRAIN_SCALE
+    noise.inputs["Detail"].default_value = 6.0
+    noise.inputs["Roughness"].default_value = 0.62
+    nt.links.new(shift.outputs["Vector"], noise.inputs["Vector"])
+    ramp = nt.nodes.new("ShaderNodeValToRGB")
+    ramp.color_ramp.elements[0].position = 0.30
+    ramp.color_ramp.elements[0].color = (0.12, 0.052, 0.018, 1.0)
+    ramp.color_ramp.elements[1].position = 0.72
+    ramp.color_ramp.elements[1].color = (0.38, 0.18, 0.065, 1.0)
+    nt.links.new(noise.outputs["Fac"], ramp.inputs["Fac"])
+    gain = nt.nodes.new("ShaderNodeMath")
+    gain.operation = "MULTIPLY_ADD"
+    gain.inputs[1].default_value = 1.1
+    gain.inputs[2].default_value = 0.45
+    nt.links.new(tone.outputs["Fac"], gain.inputs[0])
+    mix = nt.nodes.new("ShaderNodeMix")
+    mix.data_type = "RGBA"
+    mix.blend_type = "MULTIPLY"
+    _sock(mix.inputs, "Factor_Float").default_value = 1.0
+    nt.links.new(ramp.outputs["Color"], _sock(mix.inputs, "A_Color"))
+    nt.links.new(gain.outputs["Value"], _sock(mix.inputs, "B_Color"))
+    nt.links.new(_sock(mix.outputs, "Result_Color"), bsdf.inputs["Base Color"])
+    rough = nt.nodes.new("ShaderNodeMapRange")
+    rough.inputs["To Min"].default_value = 0.72
+    rough.inputs["To Max"].default_value = 0.52
+    nt.links.new(noise.outputs["Fac"], rough.inputs["Value"])
+    nt.links.new(rough.outputs["Result"], bsdf.inputs["Roughness"])
+    return mat
+
+
+def clip_x(ring, x, keep_above):
+    """Sutherland-Hodgman clip of a closed xy ring against the line X = x."""
+    out = []
+    n = len(ring)
+    for i in range(n):
+        p, q = ring[i], ring[(i + 1) % n]
+        p_in = p[0] >= x if keep_above else p[0] <= x
+        q_in = q[0] >= x if keep_above else q[0] <= x
+        if p_in:
+            out.append(p)
+        if p_in != q_in:
+            t = (x - p[0]) / (q[0] - p[0])
+            out.append((x, p[1] + t * (q[1] - p[1])))
+    # a cut landing on an existing vertex would leave a zero-length edge
+    clean = []
+    for p in out:
+        if not clean or math.dist(p, clean[-1]) > 1e-4:
+            clean.append(p)
+    if len(clean) > 2 and math.dist(clean[0], clean[-1]) <= 1e-4:
+        clean.pop()
+    return clean
+
+
+def add_board_disk(bm, z0, z1, xy_ring, mat_idx, n_boards):
+    """A head of ``n_boards`` boards, the outline cut across X with seams between.
+
+    Each board is the croze outline clipped to its strip, so the outer
+    edge of every board is still the croze and the head seats exactly
+    as the one-piece disk did.
+    """
+    xs = [p[0] for p in xy_ring]
+    x_lo, x_hi = min(xs), max(xs)
+    w = (x_hi - x_lo) / n_boards
+    for k in range(n_boards):
+        ring = xy_ring
+        if k > 0:
+            ring = clip_x(ring, x_lo + k * w + BOARD_SEAM * 0.5, True)
+        if k < n_boards - 1:
+            ring = clip_x(ring, x_lo + (k + 1) * w - BOARD_SEAM * 0.5, False)
+        add_polygon_disk(bm, z0, z1, ring, mat_idx)
+
+
+def board_audit(me, z_lo, z_hi):
+    """Boards of the flat wooden disk between ``z_lo`` and ``z_hi``: count and seams.
+
+    A board is a thin wooden shell wide in plan. Sorted across X, the
+    seam is the gap between one board's max X and the next one's min X.
+    """
+    boards = []
+    for g in shells(me):
+        if mat_of(me, g) != WOOD_IDX:
+            continue
+        a = shell_aabb(me, g)
+        if a[5] - a[2] > 0.06 or max(a[3] - a[0], a[4] - a[1]) < BOARD_MIN_SPAN:
+            continue
+        if not (z_lo <= 0.5 * (a[2] + a[5]) <= z_hi):
+            continue
+        boards.append(a)
+    boards.sort(key=lambda a: a[0])
+    seams = [boards[i + 1][0] - boards[i][3] for i in range(len(boards) - 1)]
+    return len(boards), seams
+
+
+def barrel_materials():
+    """(wood, iron): shared by the check, the render and inspection."""
+    wood = wood_material("BarrelWood")
+    metal = principled(
+        "BarrelHoop", (0.17, 0.165, 0.155, 1.0), 0.80, 0.46,
+        noise_scale=18.0, wear=(0.20, 0.085, 0.032, 1.0),
+    )
+    return wood, metal
+
+
 def body_plan(me):
     groups = shells(me)
     xs, ys, z0s, z1s = [], [], [], []
@@ -834,23 +1034,20 @@ def check(
     short_staves=False,
     float_head=False,
     round_band=False,
+    one_piece_head=False,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=True)
     flags = dict(
         short_staves=short_staves,
         float_head=float_head,
         round_band=round_band,
+        one_piece_head=one_piece_head,
     )
     low = build_barrel_mesh("BarrelLow", 0.004, 2, **flags)
     high = build_barrel_mesh("BarrelHigh", 0.004, 4, **flags)
-    wood = principled(
-        "BarrelWood", (0.48, 0.22, 0.07, 1.0), 0.0, 0.50,
-        noise_scale=7.0, wear=(0.28, 0.14, 0.05, 1.0),
-    )
-    metal = principled(
-        "BarrelHoop", (0.55, 0.53, 0.50, 1.0), 1.0, 0.28,
-        noise_scale=5.0, wear=(0.35, 0.32, 0.28, 1.0),
-    )
+    wood, metal = barrel_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
     if stray_vert:
@@ -883,6 +1080,9 @@ def check(
     sup = support_audit(low.data)
     bite_min, bite_max = hoop_seat(low.data, spans)
     hgap = head_gap(low.data, spans)
+    boards_bot, seams_bot = board_audit(low.data, 0.0, 0.2)
+    boards_top, seams_top = board_audit(low.data, HEIGHT - 0.2, HEIGHT + 0.2)
+    seams = seams_bot + seams_top
     dia, ht = body_plan(low.data)
     print(
         f"measured hygiene loose_v={hyg['loose_v']} loose_e={hyg['loose_e']} "
@@ -894,6 +1094,10 @@ def check(
         f"hoop_bite={bite_min:.5f}..{bite_max:.5f} head_gap={hgap:.5f} "
         f"body={dia:.4f}x{ht:.4f}"
     )
+    print(
+        f"measured head_boards={boards_bot}+{boards_top} "
+        f"seams={min(seams, default=0.0):.5f}..{max(seams, default=0.0):.5f}"
+    )
 
     img, tex = setup_bake_image(low, wood)
     if img is None:
@@ -921,6 +1125,10 @@ def check(
         os.remove(export_path)
     export_unity(export_path, [low, collider])
     export_size = os.path.getsize(export_path) if os.path.isfile(export_path) else 0
+    # Blender points TMPDIR at the working directory, so the export must not
+    # outlive the measurement.
+    if os.path.exists(export_path):
+        os.remove(export_path)
 
     print(f"blender={tuple(bpy.app.version)} skip_decimate={skip_decimate}")
     print(
@@ -1035,6 +1243,19 @@ def check(
             "(--float-head is the designed fail)",
             17,
         ), None, None, None, None, None
+    if (
+        boards_bot != HEAD_BOARDS
+        or boards_top != HEAD_BOARDS
+        or min(seams, default=0.0) < BOARD_SEAM_MIN
+        or max(seams, default=99.0) > BOARD_SEAM_MAX
+    ):
+        return fail(
+            f"head boards {boards_bot}+{boards_top} != {HEAD_BOARDS} each, or "
+            f"seams {min(seams, default=0.0):.5f}..{max(seams, default=0.0):.5f} "
+            f"outside [{BOARD_SEAM_MIN}, {BOARD_SEAM_MAX}] "
+            "(--one-piece-head is the designed fail)",
+            17,
+        ), None, None, None, None, None
     if bite_min < HOOP_BITE_MIN or bite_max > HOOP_BITE_MAX:
         return fail(
             f"hoop bite {bite_min:.5f}..{bite_max:.5f} "
@@ -1165,6 +1386,7 @@ def main():
     p.add_argument("--short-staves", action="store_true")
     p.add_argument("--float-head", action="store_true")
     p.add_argument("--round-band", action="store_true")
+    p.add_argument("--one-piece-head", action="store_true")
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1174,6 +1396,7 @@ def main():
         short_staves=args.short_staves,
         float_head=args.float_head,
         round_band=args.round_band,
+        one_piece_head=args.one_piece_head,
     )
     if code:
         return code
diff --git a/showcase/wooden-bucket/README.md b/showcase/wooden-bucket/README.md
index 4c48f5da..7fee9aec 100644
--- a/showcase/wooden-bucket/README.md
+++ b/showcase/wooden-bucket/README.md
@@ -1,9 +1,9 @@
 # Wooden bucket
 
 A showcase piece, not an example. Procedural coopered pail (16 staves
-with seeded width jitter, a bottom seated in a croze above a chime,
-iron hoops lofted on the stave faces, ear plates and rings, a round
-rope bail through the rings) then the shipped pipeline: unique-cell
+with seeded width jitter, a bottom of three boards seated in a croze
+above a chime, iron hoops lofted on the stave faces, ear plates and
+rings, a three-strand rope bail through the rings) then the shipped pipeline: unique-cell
 UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity
 glTF export.
 
@@ -11,8 +11,10 @@ Hoops evaluate the same `host_outer_r` chord as the stave flats.
 `--round-band` is the falsifier: a circle of `radius_at(z)` instead of
 the chord. The floor follows the inner stave polygon. Ear plates sit on
 the outer stave face below the rim; the bail is a semicircle whose ends
-pass through the rings. `--float-handle` shrinks that semicircle so the
-bar sits on the ring; `--float-bottom` shrinks the floor out of the croze.
+pass through the rings and run on below them. `--float-handle` shrinks
+that semicircle and lifts it by what it lost, so the envelope stays put
+and only the bail-ear gap fails; `--float-bottom` shrinks the floor out
+of the croze.
 
 It asserts **budget conformance** of the generated result. It does not
 witness an API contract. "It rendered without error" is not a check.
@@ -30,26 +32,27 @@ materials, UVs, evaluated LOD, collider, or export file.
 
 | Axis | Declared | Measured (4.5.11 / 5.1.2 / 5.2.1) |
 | --- | --- | --- |
-| Base triangles | 4000–5800 | 4872 / 4872 / 4872 |
-| LOD1 ratio | 0.32–0.62 of base | 0.5000 / 0.5000 / 0.5000 |
-| LOD2 ratio | 0.10–0.35 of base | 0.2196 / 0.2196 / 0.2188 |
-| Materials | exactly 3 distinct; ≥350 wood, ≥180 metal, ≥40 rope | 3 slots; 1424 / 1020 / 208 |
+| Base triangles | 4000–5800 | 5458 / 5458 / 5458 |
+| LOD1 ratio | 0.32–0.62 of base | 0.4998 / 0.4998 / 0.4998 |
+| LOD2 ratio | 0.10–0.35 of base | 0.2199 / 0.2199 / 0.2191 |
+| Materials | exactly 3 distinct; ≥350 wood, ≥180 metal, ≥40 rope | 3 slots; 1448 / 1020 / 486 |
 | UVs | in `0..1`, AABB overlap ≤ 1e-5 | in range, overlap 0 |
-| Outer AABB | (0.383, 0.346, 0.527) m ± 0.015 | (0.3832, 0.3462, 0.5271), zmin 0 |
-| Collider tris | ≤ 420 | 302 |
-| Export | written, size > 0 | 378296 / 378296 / 378276 bytes |
+| Outer AABB | (0.396, 0.346, 0.534) m ± 0.015 | (0.3957, 0.3462, 0.5338), zmin 0 |
+| Collider tris | ≤ 420 | 276 |
+| Export | written, size > 0 | 420984 / 420984 / 420976 bytes |
 
 Base triangles rose from **4272 to 4872** in the quality pass: overlapping
 identical staves, circular hoops, and a 12-box bail became 16 jittered
 staves, chord-seated hoops, a polygonal croze floor, and a round bail
-through the ear rings.
+through the ear rings. The second pass took it to **5458**: the bail
+became three-strand rope (48 segments of a nine-vertex lobed section,
+running on through the rings) and the floor three boards.
 
-DECIMATE COLLAPSE triangle counts are **not** identical across series —
-5.2.1 is 4 tris leaner on LOD2. The gate is a ratio band, not an exact
+DECIMATE COLLAPSE triangle counts are **not** identical across series,
+so LOD2 ratios differ slightly between versions. The gate is a ratio band, not an exact
 count. Bake pixels are stochastic; the gate is `has_data` plus operator
 `FINISHED`, not byte-identity. Stave-width jitter uses fixed seed 17.
-Export byte counts differ by 20 B on 5.2.1 (glTF serializer), not a
-gated axis.
+Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis.
 
 ### Hygiene
 
@@ -71,13 +74,15 @@ Recomputed from the generated mesh, not asserted about the script.
 
 | Axis | Declared | Measured (all three) |
 | --- | --- | --- |
-| Bail-ear BVH gap | ≤ 0.006 m | 0.00125 |
-| Floor-croze rim BVH gap | ≤ 0.008 m | 0.00458 |
+| Bail-ear BVH gap | ≤ 0.006 m | 0.00107 |
+| Floor-croze rim BVH gap | ≤ 0.008 m | 0.00474 |
+| Bottom boards | 3; every seam 0.0006–0.0025 m | 3; 0.00120 |
+| Rope clears the ear plates | 2 plates; 0 rope vertices inside either | 2; 0 |
 | Hoop bite (host r − inner hoop r) | 0.0010–0.007 m | 0.00250 |
 
 ### Falsifiers
 
-Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and
+Each violates one named budget. All nine were run on 4.5.11, 5.1.2 and
 5.2.1 and returned the same code on each.
 
 | Flag | Budget violated | Exit |
@@ -89,6 +94,31 @@ Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and
 | `--float-handle` | bail-ear gap | 17 |
 | `--float-bottom` | floor-croze gap | 17 |
 | `--round-band` | hoop bite band | 18 |
+| `--one-piece-bottom` | bottom boards: 3 | 17 |
+| `--sunk-rope` | rope clears the ear plates | 17 |
+
+## Rope and ears
+
+The bail was a smooth eight-sided tube in a rope material, and it read as
+a plastic hose. It is now laid rope: a three-lobed section turned one
+vertex step per ring, so the lobes wind along the bail as strands. The
+section's frame is fixed to the bail's plane, so the lay does not jump
+where the ends turn vertical.
+
+The ring offset from the ear plate was `RING_MAJOR * 0.25`, which put the
+rope's axis 3.25 mm off the plate and its body through it (hidden by the
+ring in the old stills). The offset is now sized from the rope's lobes
+plus 0.5 mm, and **Rope clears the ear plates** asserts it. `--sunk-rope`
+restores the old offset and puts 19 rope vertices inside a plate. The
+outer AABB was re-fitted to the honest envelope: 12.5 mm wider across the
+ears and 6 mm taller.
+
+## Surface
+
+Every stave and board carries a seeded `PlankTone` and a `GrainDir` (its
+own long axis) as face attributes, and `wood_material` stretches grain
+along that axis. The hoops, plates and rings are dark rusted iron. The
+temp `.glb` is removed once its size is measured.
 
 ## Run
 
@@ -101,6 +131,8 @@ blender --background --python wooden_bucket.py -- --short-staves
 blender --background --python wooden_bucket.py -- --float-handle
 blender --background --python wooden_bucket.py -- --float-bottom
 blender --background --python wooden_bucket.py -- --round-band
+blender --background --python wooden_bucket.py -- --one-piece-bottom
+blender --background --python wooden_bucket.py -- --sunk-rope
 blender --background --python wooden_bucket.py -- --output bucket.png
 ```
 
@@ -131,6 +163,6 @@ hygiene and joint-fit family.
 | 14 | `--output` produced no file |
 | 15 | Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight |
 | 16 | Not grounded: bounding box `zmin` off 0, or a named stave floats |
-| 17 | Joint fit: bail-ear gap or floor-croze gap |
+| 17 | Joint fit: bail-ear gap, floor-croze gap, bottom boards and seams, or rope through an ear plate |
 | 18 | Seat: hoop bite band (`--round-band`) |
 | 19 | Body diameter or height off the stated real-world size |
diff --git a/showcase/wooden-bucket/preview.webp b/showcase/wooden-bucket/preview.webp
index 24570e8c..fdb502a0 100644
Binary files a/showcase/wooden-bucket/preview.webp and b/showcase/wooden-bucket/preview.webp differ
diff --git a/showcase/wooden-bucket/wooden_bucket.py b/showcase/wooden-bucket/wooden_bucket.py
index a4bbb89a..def8a2d2 100644
--- a/showcase/wooden-bucket/wooden_bucket.py
+++ b/showcase/wooden-bucket/wooden_bucket.py
@@ -16,7 +16,8 @@
 budget: ``--skip-decimate`` the LOD-ratio band, ``--stray-vert`` mesh
 hygiene, ``--lift-z`` grounded zmin, ``--short-staves`` named stave
 supports, ``--float-handle`` bail-ear joint-fit, ``--float-bottom``
-floor-croze joint-fit, ``--round-band`` hoop seat (hoop generated on a
+floor-croze joint-fit, ``--one-piece-bottom`` bottom boards (one slab
+instead of boards), ``--round-band`` hoop seat (hoop generated on a
 circle instead of the stave chords).
 
 Fixed seed 17 for stave-width jitter. DECIMATE COLLAPSE triangle counts
@@ -69,12 +70,23 @@
 CHIME = 0.008
 CROZE_BITE = 0.0025
 FLOOR_GAP_MAX = 0.008
-BAIL_R = 0.008
-BAIL_SEGS = 24
-BAIL_PIPE = 8
+BAIL_R = 0.0075
+BAIL_SEGS = 48
+# The bail is three-strand rope: a three-lobed section of ROPE_PIPE verts
+# turned one vertex step per ring, so the lobes run as helical strands.
+# Lobes reach BAIL_R * (1 + ROPE_LOBE), inside the ear ring's hole
+# (RING_MAJOR - RING_MINOR). Each end runs ROPE_TAIL on through its ring.
+# The ring centre stands ROPE_CLEAR beyond the rope's lobes off the ear
+# plate, so the rope passes the plate instead of through it.
+ROPE_PIPE = 9
+ROPE_LOBE = 0.20
+ROPE_TAIL = 0.014
+ROPE_CLEAR = 0.0005
 EAR_Z = HEIGHT - 0.016
 RING_MAJOR = 0.013
 RING_MINOR = 0.0035
+RING_OFFSET = BAIL_R * (1.0 + ROPE_LOBE) + ROPE_CLEAR
+SUNK_RING_OFFSET = RING_MAJOR * 0.25
 BAIL_GAP_MAX = 0.006
 STAVE_ZMIN_MAX = 0.001
 SHORT_STAVES_LIFT = 0.040
@@ -88,7 +100,7 @@
 BODY_DIA = 0.335
 BODY_H = 0.360
 BBOX_TOL = 0.015
-OUTER_SIZE = (0.383, 0.346, 0.527)
+OUTER_SIZE = (0.396, 0.346, 0.534)
 
 BASE_TRIS_MIN = 4000
 BASE_TRIS_MAX = 5800
@@ -113,6 +125,19 @@
 METAL_IDX = 1
 ROPE_IDX = 2
 
+# The bottom is BOTTOM_BOARDS boards cut across X from the croze outline,
+# with a BOARD_SEAM between neighbours. A board is a thin wooden shell at
+# least BOARD_MIN_SPAN wide in plan (the narrowest board is 0.20).
+BOTTOM_BOARDS = 3
+BOARD_SEAM = 0.0012
+BOARD_SEAM_MIN = 0.0006
+BOARD_SEAM_MAX = 0.0025
+BOARD_MIN_SPAN = 0.15
+# Per-piece wood tone jitter and grain frequency, as in shipping-crate.
+PLANK_TONE_JITTER = 0.28
+TONE_SEED = 29
+WOOD_GRAIN_SCALE = 45.0
+
 
 def eevee_engine_id():
     return "BLENDER_EEVEE" if bpy.app.version >= (5, 0, 0) else "BLENDER_EEVEE_NEXT"
@@ -272,7 +297,15 @@ def add_torus(bm, loc, major, minor, n_major, n_minor, mat_idx, euler=(0.0, 0.0,
     return verts
 
 
-def add_pipe_curve(bm, points, radius, segs, mat_idx):
+def add_rope_curve(bm, points, radius, mat_idx):
+    """Three-strand rope along a path in the XZ plane.
+
+    The section is ROPE_PIPE verts with three lobes, turned one vertex
+    step per ring, so each lobe winds along the path as a strand. The
+    frame is fixed to the path's plane (side = +Y), so the lay never
+    jumps where the path turns vertical.
+    """
+    side = Vector((0.0, 1.0, 0.0))
     rings = []
     n = len(points)
     for i, p in enumerate(points):
@@ -281,20 +314,13 @@ def add_pipe_curve(bm, points, radius, segs, mat_idx):
             tangent = (Vector(points[i + 1]) - p).normalized()
         else:
             tangent = (p - Vector(points[i - 1])).normalized()
-        side = Vector((-tangent.y, tangent.x, 0.0))
-        if side.length < 1e-6:
-            side = Vector((1.0, 0.0, 0.0))
-        else:
-            side.normalize()
         up = tangent.cross(side).normalized()
         ring = []
-        for k in range(segs):
-            a = 2.0 * math.pi * k / segs
-            ring.append(
-                bm.verts.new(
-                    p + side * (radius * math.cos(a)) + up * (radius * math.sin(a))
-                )
-            )
+        for k in range(ROPE_PIPE):
+            a = 2.0 * math.pi * k / ROPE_PIPE
+            lobe = 1.0 + ROPE_LOBE * math.cos(3.0 * a - 2.0 * math.pi * 3.0 * i / ROPE_PIPE)
+            r = radius * lobe
+            ring.append(bm.verts.new(p + side * (r * math.cos(a)) + up * (r * math.sin(a))))
         rings.append(ring)
     loft_rings(bm, rings, mat_idx, cap_start=True, cap_end=True)
 
@@ -408,7 +434,7 @@ def triangulate_ngons(bm):
         bmesh.ops.triangulate(bm, faces=faces)
 
 
-def add_ears_and_bail(bm, spans, float_handle):
+def add_ears_and_bail(bm, spans, float_handle, sunk_rope=False):
     """Ear plates + flat rings (hole along Z) and a round bail through them.
 
     Ring centres sit on the stave outer at EAR_Z. The bail is a semicircle
@@ -425,8 +451,11 @@ def add_ears_and_bail(bm, spans, float_handle):
     plate_z = HEIGHT - plate_h * 0.5 - 0.006
     x_l = -(r_l + plate_t * 0.5)
     x_r = r_r + plate_t * 0.5
-    ring_x_l = -(r_l + plate_t + RING_MAJOR * 0.25)
-    ring_x_r = r_r + plate_t + RING_MAJOR * 0.25
+    # --sunk-rope restores the old offset, a quarter of the ring's major
+    # radius: the rope's axis 3 mm off the plate, its body through it.
+    off = SUNK_RING_OFFSET if sunk_rope else RING_OFFSET
+    ring_x_l = -(r_l + plate_t + off)
+    ring_x_r = r_r + plate_t + off
     for x in (x_l, x_r):
         add_box(
             bm,
@@ -447,15 +476,21 @@ def add_ears_and_bail(bm, spans, float_handle):
         )
     rx = 0.5 * (abs(ring_x_l) + abs(ring_x_r))
     if float_handle:
+        # a smaller bail lifted by exactly what it lost, so its top and the
+        # envelope stay put and only the bail-ear gap fails
+        z0 = EAR_Z + 0.28 * rx
         rx *= 0.72
-        z0 = EAR_Z + 0.035
     else:
         z0 = EAR_Z
-    pts = []
+    # below each ring the rope runs on down ROPE_TAIL, so it passes
+    # through the ring instead of stopping inside it
+    tail = (-ROPE_TAIL, -0.5 * ROPE_TAIL)
+    pts = [(rx, 0.0, z0 + dz) for dz in tail]
     for i in range(BAIL_SEGS + 1):
         t = math.pi * i / BAIL_SEGS
         pts.append((rx * math.cos(t), 0.0, z0 + rx * math.sin(t)))
-    add_pipe_curve(bm, pts, BAIL_R, BAIL_PIPE, ROPE_IDX)
+    pts.extend((-rx, 0.0, z0 + dz) for dz in reversed(tail))
+    add_rope_curve(bm, pts, BAIL_R, ROPE_IDX)
 
 
 def pack_uvs(bm, margin=0.08):
@@ -507,6 +542,8 @@ def build_bucket_mesh(
     float_handle=False,
     round_band=False,
     float_bottom=False,
+    one_piece_bottom=False,
+    sunk_rope=False,
 ):
     bm = bmesh.new()
     gap_ang = GAP_M / max(R_TOP, 0.1)
@@ -517,13 +554,13 @@ def build_bucket_mesh(
         bot_z0 = CHIME
         bot_z1 = CHIME + BOTTOM_T
         shrink = 0.022 if float_bottom else 0.0
-        add_polygon_disk(
+        add_board_disk(
             bm, bot_z0, bot_z1,
             croze_xy(spans, 0.5 * (bot_z0 + bot_z1), CROZE_BITE, shrink),
-            WOOD_IDX,
+            WOOD_IDX, 1 if one_piece_bottom else BOTTOM_BOARDS,
         )
         build_hoops(bm, spans, round_band)
-        add_ears_and_bail(bm, spans, float_handle)
+        add_ears_and_bail(bm, spans, float_handle, sunk_rope)
         triangulate_ngons(bm)
         pack_uvs(bm)
         bmesh.ops.recalc_face_normals(bm, faces=list(bm.faces))
@@ -758,8 +795,7 @@ def floor_gap(me):
             continue
         a = shell_aabb(me, g)
         dz = a[5] - a[2]
-        r = 0.25 * ((a[3] - a[0]) + (a[4] - a[1]))
-        if dz < 0.05 and r > 0.08:
+        if dz < 0.05 and max(a[3] - a[0], a[4] - a[1]) >= BOARD_MIN_SPAN:
             floors.append(g)
         elif dz > 0.20:
             staves.append(g)
@@ -831,6 +867,221 @@ def bail_join(me):
         bm_b.free()
 
 
+def _long_axis(pts):
+    """Principal axis of a point set, by power iteration on its covariance."""
+    c = sum(pts, Vector()) / len(pts)
+    cov = [[0.0] * 3 for _ in range(3)]
+    for p in pts:
+        d = p - c
+        for i in range(3):
+            for j in range(3):
+                cov[i][j] += d[i] * d[j]
+    v = Vector((1.0, 0.3, 0.1))
+    for _ in range(30):
+        w = Vector([sum(cov[i][j] * v[j] for j in range(3)) for i in range(3)])
+        if w.length < 1e-12:
+            break
+        v = w.normalized()
+    return v
+
+
+def paint_planks(me):
+    """Per-shell ``PlankTone`` and ``GrainDir`` face attributes for the wood shader.
+
+    Every stave and every board is its own shell, so each gets one tone and
+    grain running along its own long axis (up the curved staves, across
+    the flat boards).
+    """
+    tone = [0.5] * len(me.polygons)
+    grain = [(0.0, 0.0, 1.0)] * len(me.polygons)
+    owner = {}
+    rng = random.Random(TONE_SEED)
+    for g in shells(me):
+        pts = [me.vertices[i].co.copy() for i in g]
+        d = _long_axis(pts) if len(pts) > 2 else Vector((0.0, 0.0, 1.0))
+        t = 0.5 + rng.uniform(-PLANK_TONE_JITTER, PLANK_TONE_JITTER)
+        for i in g:
+            owner[i] = (t, tuple(d))
+    for poly in me.polygons:
+        t, d = owner[poly.vertices[0]]
+        tone[poly.index] = t
+        grain[poly.index] = d
+    a = me.attributes.new("PlankTone", "FLOAT", "FACE")
+    a.data.foreach_set("value", tone)
+    b = me.attributes.new("GrainDir", "FLOAT_VECTOR", "FACE")
+    b.data.foreach_set("vector", [c for v in grain for c in v])
+
+
+def _sock(sockets, identifier):
+    """A Mix-node socket by identifier; its A/B/Result names repeat per type."""
+    return next(sk for sk in sockets if sk.identifier == identifier)
+
+
+def wood_material(name):
+    """Grain along each stave or board (``GrainDir``), tone per piece (``PlankTone``)."""
+    mat = bpy.data.materials.new(name)
+    mat.use_nodes = True
+    nt = mat.node_tree
+    bsdf = nt.nodes["Principled BSDF"]
+    coord = nt.nodes.new("ShaderNodeTexCoord")
+    gdir = nt.nodes.new("ShaderNodeAttribute")
+    gdir.attribute_name = "GrainDir"
+    tone = nt.nodes.new("ShaderNodeAttribute")
+    tone.attribute_name = "PlankTone"
+    dot = nt.nodes.new("ShaderNodeVectorMath")
+    dot.operation = "DOT_PRODUCT"
+    nt.links.new(coord.outputs["Object"], dot.inputs[0])
+    nt.links.new(gdir.outputs["Vector"], dot.inputs[1])
+    squash = nt.nodes.new("ShaderNodeMath")
+    squash.operation = "MULTIPLY"
+    squash.inputs[1].default_value = 0.94
+    nt.links.new(dot.outputs["Value"], squash.inputs[0])
+    along = nt.nodes.new("ShaderNodeVectorMath")
+    along.operation = "SCALE"
+    nt.links.new(gdir.outputs["Vector"], along.inputs[0])
+    nt.links.new(squash.outputs["Value"], along.inputs["Scale"])
+    grain_co = nt.nodes.new("ShaderNodeVectorMath")
+    grain_co.operation = "SUBTRACT"
+    nt.links.new(coord.outputs["Object"], grain_co.inputs[0])
+    nt.links.new(along.outputs["Vector"], grain_co.inputs[1])
+    shift = nt.nodes.new("ShaderNodeVectorMath")
+    shift.operation = "ADD"
+    nt.links.new(grain_co.outputs["Vector"], shift.inputs[0])
+    nt.links.new(tone.outputs["Fac"], shift.inputs[1])
+    noise = nt.nodes.new("ShaderNodeTexNoise")
+    noise.inputs["Scale"].default_value = WOOD_GRAIN_SCALE
+    noise.inputs["Detail"].default_value = 6.0
+    noise.inputs["Roughness"].default_value = 0.62
+    nt.links.new(shift.outputs["Vector"], noise.inputs["Vector"])
+    ramp = nt.nodes.new("ShaderNodeValToRGB")
+    ramp.color_ramp.elements[0].position = 0.30
+    ramp.color_ramp.elements[0].color = (0.12, 0.052, 0.018, 1.0)
+    ramp.color_ramp.elements[1].position = 0.72
+    ramp.color_ramp.elements[1].color = (0.38, 0.18, 0.065, 1.0)
+    nt.links.new(noise.outputs["Fac"], ramp.inputs["Fac"])
+    gain = nt.nodes.new("ShaderNodeMath")
+    gain.operation = "MULTIPLY_ADD"
+    gain.inputs[1].default_value = 1.1
+    gain.inputs[2].default_value = 0.45
+    nt.links.new(tone.outputs["Fac"], gain.inputs[0])
+    mix = nt.nodes.new("ShaderNodeMix")
+    mix.data_type = "RGBA"
+    mix.blend_type = "MULTIPLY"
+    _sock(mix.inputs, "Factor_Float").default_value = 1.0
+    nt.links.new(ramp.outputs["Color"], _sock(mix.inputs, "A_Color"))
+    nt.links.new(gain.outputs["Value"], _sock(mix.inputs, "B_Color"))
+    nt.links.new(_sock(mix.outputs, "Result_Color"), bsdf.inputs["Base Color"])
+    rough = nt.nodes.new("ShaderNodeMapRange")
+    rough.inputs["To Min"].default_value = 0.72
+    rough.inputs["To Max"].default_value = 0.52
+    nt.links.new(noise.outputs["Fac"], rough.inputs["Value"])
+    nt.links.new(rough.outputs["Result"], bsdf.inputs["Roughness"])
+    return mat
+
+
+def clip_x(ring, x, keep_above):
+    """Sutherland-Hodgman clip of a closed xy ring against the line X = x."""
+    out = []
+    n = len(ring)
+    for i in range(n):
+        p, q = ring[i], ring[(i + 1) % n]
+        p_in = p[0] >= x if keep_above else p[0] <= x
+        q_in = q[0] >= x if keep_above else q[0] <= x
+        if p_in:
+            out.append(p)
+        if p_in != q_in:
+            t = (x - p[0]) / (q[0] - p[0])
+            out.append((x, p[1] + t * (q[1] - p[1])))
+    # a cut landing on an existing vertex would leave a zero-length edge
+    clean = []
+    for p in out:
+        if not clean or math.dist(p, clean[-1]) > 1e-4:
+            clean.append(p)
+    if len(clean) > 2 and math.dist(clean[0], clean[-1]) <= 1e-4:
+        clean.pop()
+    return clean
+
+
+def add_board_disk(bm, z0, z1, xy_ring, mat_idx, n_boards):
+    """A disk of ``n_boards`` boards, the outline cut across X with seams between.
+
+    Each board is the croze outline clipped to its strip, so the outer
+    edge of every board is still the croze and the bottom seats exactly
+    as the one-piece disk did.
+    """
+    xs = [p[0] for p in xy_ring]
+    x_lo, x_hi = min(xs), max(xs)
+    w = (x_hi - x_lo) / n_boards
+    for k in range(n_boards):
+        ring = xy_ring
+        if k > 0:
+            ring = clip_x(ring, x_lo + k * w + BOARD_SEAM * 0.5, True)
+        if k < n_boards - 1:
+            ring = clip_x(ring, x_lo + (k + 1) * w - BOARD_SEAM * 0.5, False)
+        add_polygon_disk(bm, z0, z1, ring, mat_idx)
+
+
+def board_audit(me, z_lo, z_hi):
+    """Boards of the flat wooden disk between ``z_lo`` and ``z_hi``: count and seams.
+
+    A board is a thin wooden shell wide in plan. Sorted across X, the
+    seam is the gap between one board's max X and the next one's min X.
+    """
+    boards = []
+    for g in shells(me):
+        if mat_of(me, g) != WOOD_IDX:
+            continue
+        a = shell_aabb(me, g)
+        if a[5] - a[2] > 0.06 or max(a[3] - a[0], a[4] - a[1]) < BOARD_MIN_SPAN:
+            continue
+        if not (z_lo <= 0.5 * (a[2] + a[5]) <= z_hi):
+            continue
+        boards.append(a)
+    boards.sort(key=lambda a: a[0])
+    seams = [boards[i + 1][0] - boards[i][3] for i in range(len(boards) - 1)]
+    return len(boards), seams
+
+
+def bucket_materials():
+    """(wood, iron, rope): shared by the check, the render and inspection."""
+    wood = wood_material("BucketWood")
+    metal = principled(
+        "BucketHoop", (0.17, 0.165, 0.155, 1.0), 0.80, 0.46,
+        noise_scale=18.0, wear=(0.20, 0.085, 0.032, 1.0),
+    )
+    rope = principled(
+        "BucketRope", (0.50, 0.40, 0.24, 1.0), 0.0, 0.80,
+        noise_scale=60.0, wear=(0.30, 0.22, 0.12, 1.0),
+    )
+    return wood, metal, rope
+
+
+def rope_through_plates(me):
+    """Rope vertices inside an ear plate's box: the rope must pass the plates.
+
+    The ear plates are the two eight-vertex iron shells high on the
+    bucket. A rope vertex strictly inside either box is rope running
+    through iron.
+    """
+    plates, rope = [], []
+    for g in shells(me):
+        mat = mat_of(me, g)
+        if mat == METAL_IDX and len(g) == 8 and shell_aabb(me, g)[2] > 0.25:
+            plates.append(shell_aabb(me, g))
+        elif mat == ROPE_IDX:
+            rope.extend(g)
+    eps = 1e-5
+    inside = 0
+    for i in rope:
+        p = me.vertices[i].co
+        for a in plates:
+            if (a[0] + eps < p.x < a[3] - eps and a[1] + eps < p.y < a[4] - eps
+                    and a[2] + eps < p.z < a[5] - eps):
+                inside += 1
+                break
+    return len(plates), inside
+
+
 def body_plan(me):
     groups = shells(me)
     xs, ys, z0s, z1s = [], [], [], []
@@ -965,6 +1216,8 @@ def check(
     float_handle=False,
     round_band=False,
     float_bottom=False,
+    one_piece_bottom=False,
+    sunk_rope=False,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=True)
     flags = dict(
@@ -972,21 +1225,14 @@ def check(
         float_handle=float_handle,
         round_band=round_band,
         float_bottom=float_bottom,
+        one_piece_bottom=one_piece_bottom,
+        sunk_rope=sunk_rope,
     )
     low = build_bucket_mesh("BucketLow", 0.003, 2, **flags)
     high = build_bucket_mesh("BucketHigh", 0.003, 4, **flags)
-    wood = principled(
-        "BucketWood", (0.46, 0.24, 0.09, 1.0), 0.0, 0.52,
-        noise_scale=7.0, wear=(0.28, 0.14, 0.05, 1.0),
-    )
-    metal = principled(
-        "BucketHoop", (0.55, 0.53, 0.50, 1.0), 1.0, 0.28,
-        noise_scale=5.0, wear=(0.35, 0.32, 0.28, 1.0),
-    )
-    rope = principled(
-        "BucketRope", (0.42, 0.32, 0.18, 1.0), 0.0, 0.72,
-        noise_scale=9.0, wear=(0.30, 0.22, 0.12, 1.0),
-    )
+    wood, metal, rope = bucket_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal, rope)
     assign_slots(high, wood, metal, rope)
     if stray_vert:
@@ -1020,6 +1266,8 @@ def check(
     bite_min, bite_max = hoop_seat(low.data, spans)
     bjoin = bail_join(low.data)
     fgap = floor_gap(low.data)
+    n_boards, seams = board_audit(low.data, 0.0, 0.1)
+    n_plates, rope_in_plate = rope_through_plates(low.data)
     dia, ht = body_plan(low.data)
     print(
         f"measured hygiene loose_v={hyg['loose_v']} loose_e={hyg['loose_e']} "
@@ -1031,6 +1279,11 @@ def check(
         f"hoop_bite={bite_min:.5f}..{bite_max:.5f} bail_join={bjoin:.5f} "
         f"floor_gap={fgap:.5f} body={dia:.4f}x{ht:.4f}"
     )
+    print(
+        f"measured bottom_boards={n_boards} "
+        f"seams={min(seams, default=0.0):.5f}..{max(seams, default=0.0):.5f} "
+        f"ear_plates={n_plates} rope_in_plate={rope_in_plate}"
+    )
 
     img, tex = setup_bake_image(low, wood)
     if img is None:
@@ -1058,6 +1311,10 @@ def check(
         os.remove(export_path)
     export_unity(export_path, [low, collider])
     export_size = os.path.getsize(export_path) if os.path.isfile(export_path) else 0
+    # Blender points TMPDIR at the working directory, so the export must not
+    # outlive the measurement.
+    if os.path.exists(export_path):
+        os.remove(export_path)
 
     print(f"blender={tuple(bpy.app.version)} skip_decimate={skip_decimate}")
     print(
@@ -1185,6 +1442,24 @@ def check(
             "(--float-bottom is the designed fail)",
             17,
         ), None, None, None, None, None
+    if (
+        n_boards != BOTTOM_BOARDS
+        or min(seams, default=0.0) < BOARD_SEAM_MIN
+        or max(seams, default=99.0) > BOARD_SEAM_MAX
+    ):
+        return fail(
+            f"bottom boards {n_boards} != {BOTTOM_BOARDS}, or seams "
+            f"{min(seams, default=0.0):.5f}..{max(seams, default=0.0):.5f} "
+            f"outside [{BOARD_SEAM_MIN}, {BOARD_SEAM_MAX}] "
+            "(--one-piece-bottom is the designed fail)",
+            17,
+        ), None, None, None, None, None
+    if n_plates != 2 or rope_in_plate:
+        return fail(
+            f"ear plates {n_plates} != 2, or {rope_in_plate} rope vertices "
+            "inside a plate (--sunk-rope is the designed fail)",
+            17,
+        ), None, None, None, None, None
     if bite_min < HOOP_BITE_MIN or bite_max > HOOP_BITE_MAX:
         return fail(
             f"hoop bite {bite_min:.5f}..{bite_max:.5f} "
@@ -1316,6 +1591,8 @@ def main():
     p.add_argument("--float-handle", action="store_true")
     p.add_argument("--float-bottom", action="store_true")
     p.add_argument("--round-band", action="store_true")
+    p.add_argument("--one-piece-bottom", action="store_true")
+    p.add_argument("--sunk-rope", action="store_true")
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1326,6 +1603,8 @@ def main():
         float_handle=args.float_handle,
         round_band=args.round_band,
         float_bottom=args.float_bottom,
+        one_piece_bottom=args.one_piece_bottom,
+        sunk_rope=args.sunk_rope,
     )
     if code:
         return code