diff --git a/README.md b/README.md
index 58d4a55b..47acc8b7 100644
--- a/README.md
+++ b/README.md
@@ -124,9 +124,9 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/wheelbarrow/"><img src="showcase/wheelbarrow/preview.webp" width="24%" alt="Wheelbarrow: a wooden tray with walls of stacked boards and iron straps, a spoked wheel, rear legs, and handles on a dark studio floor" /></a>
   <a href="showcase/anvil/"><img src="showcase/anvil/preview.webp" width="24%" alt="Anvil: a London-pattern anvil on a hooped timber stump on a dark studio floor" /></a>
   <a href="showcase/water-trough/"><img src="showcase/water-trough/preview.webp" width="24%" alt="Water trough: a watertight wooden trough with plank ends, contained water, and trestle legs on a dark studio floor" /></a>
-  <a href="showcase/hitching-post/"><img src="showcase/hitching-post/preview.webp" width="24%" alt="Hitching post: a square timber post with a pyramidal cap, cross-arm, iron bands, and two hitching rings on a dark studio floor" /></a>
+  <a href="showcase/hitching-post/"><img src="showcase/hitching-post/preview.webp" width="24%" alt="Hitching post: a square timber post with a pyramidal cap, cross-arm, iron bands wrapped around it, and two hitching rings on a dark studio floor" /></a>
   <a href="showcase/grindstone/"><img src="showcase/grindstone/preview.webp" width="24%" alt="Grindstone: a stone wheel on a timber A-frame with an iron axle, hubs, crank, and tray on a dark studio floor" /></a>
-  <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/hand-pump/"><img src="showcase/hand-pump/preview.webp" width="24%" alt="Hand pump: a matte black cast-iron village pump on a stepped 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 three-strand rope bail through iron ear rings and chord-lofted iron hoops on a dark studio floor" /></a>
@@ -169,7 +169,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`water-trough`](showcase/water-trough/) — procedural watertight water trough on a timber stand through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
-[`hitching-post`](showcase/hitching-post/) — procedural timber hitching post with a cross-arm and iron rings through the same pipeline. Falsifier `--skip-decimate` exits 9.
+[`hitching-post`](showcase/hitching-post/) — procedural timber hitching post with a cross-arm, wrapped iron bands and iron rings through the same pipeline. Falsifiers `--skip-decimate` exits 9, `--sunk-bands` exits 18.
 
 [`grindstone`](showcase/grindstone/) — procedural grindstone on a timber trestle with iron axle and crank through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
@@ -645,7 +645,7 @@ A slotted-actions Z-rotation turntable keyed through the cross-version channelba
 </tr>
 <tr>
 <td width="46%" valign="middle">
-<a href="examples/driver-wave/"><img src="examples/driver-wave/preview.webp" alt="Driver wave: sixteen orange columns whose heights form a sine skyline on a dark studio floor, each driven by a driver_namespace function" /></a>
+<a href="examples/driver-wave/"><img src="examples/driver-wave/preview.webp" alt="Driver wave: sixteen orange columns seen from above whose heights form a sine wave on a dark studio floor, each driven by a driver_namespace function" /></a>
 </td>
 <td valign="middle">
 
diff --git a/docs/gallery/assets/driver-wave-hero.webp b/docs/gallery/assets/driver-wave-hero.webp
index 13f8e776..09d37914 100644
Binary files a/docs/gallery/assets/driver-wave-hero.webp and b/docs/gallery/assets/driver-wave-hero.webp differ
diff --git a/docs/gallery/assets/hand-pump-hero.webp b/docs/gallery/assets/hand-pump-hero.webp
index 9760145e..61aa9a37 100644
Binary files a/docs/gallery/assets/hand-pump-hero.webp and b/docs/gallery/assets/hand-pump-hero.webp differ
diff --git a/docs/gallery/assets/hitching-post-hero.webp b/docs/gallery/assets/hitching-post-hero.webp
index 6954d2a8..4b285717 100644
Binary files a/docs/gallery/assets/hitching-post-hero.webp and b/docs/gallery/assets/hitching-post-hero.webp differ
diff --git a/docs/gallery/assets/shader-node-group-hero.webp b/docs/gallery/assets/shader-node-group-hero.webp
index 4fb7dad3..f15d876d 100644
Binary files a/docs/gallery/assets/shader-node-group-hero.webp and b/docs/gallery/assets/shader-node-group-hero.webp differ
diff --git a/docs/gallery/contact-sheets/driver-wave-contact-sheet.webp b/docs/gallery/contact-sheets/driver-wave-contact-sheet.webp
index f8f3aa1a..af518de3 100644
Binary files a/docs/gallery/contact-sheets/driver-wave-contact-sheet.webp and b/docs/gallery/contact-sheets/driver-wave-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/hand-pump-contact-sheet.webp b/docs/gallery/contact-sheets/hand-pump-contact-sheet.webp
index b5fedebd..0f0edd35 100644
Binary files a/docs/gallery/contact-sheets/hand-pump-contact-sheet.webp and b/docs/gallery/contact-sheets/hand-pump-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/hitching-post-contact-sheet.webp b/docs/gallery/contact-sheets/hitching-post-contact-sheet.webp
index 720885c9..8a6c95f4 100644
Binary files a/docs/gallery/contact-sheets/hitching-post-contact-sheet.webp and b/docs/gallery/contact-sheets/hitching-post-contact-sheet.webp differ
diff --git a/docs/gallery/contact-sheets/shader-node-group-contact-sheet.webp b/docs/gallery/contact-sheets/shader-node-group-contact-sheet.webp
index c23adfa2..8a791c3f 100644
Binary files a/docs/gallery/contact-sheets/shader-node-group-contact-sheet.webp and b/docs/gallery/contact-sheets/shader-node-group-contact-sheet.webp differ
diff --git a/docs/gallery/driver-wave/index.html b/docs/gallery/driver-wave/index.html
index 24962258..ec1dd1b5 100644
--- a/docs/gallery/driver-wave/index.html
+++ b/docs/gallery/driver-wave/index.html
@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/driver-wave-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends." />
+  <meta property="og:image:alt" content="A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the floor." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="driver-wave — Examples — Blender Developer Tools" />
   <meta name="twitter:description" content="A driver_namespace function driving sixteen column heights through SCRIPTED drivers — the sine skyline is entirely driver-evaluated." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/driver-wave-hero.webp" />
-  <meta name="twitter:image:alt" content="A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends." />
+  <meta name="twitter:image:alt" content="A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the 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>driver-wave</h1>
     <p>A driver_namespace function driving sixteen column heights through SCRIPTED drivers — the sine skyline is entirely driver-evaluated.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends.">
-      <img src="../assets/driver-wave-hero.webp" alt="A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the floor.">
+      <img src="../assets/driver-wave-hero.webp" alt="A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the 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> Driven values appear after a view-layer update in two places that must agree: the evaluated copy and the original datablock the animation system flushes for display.</div>
@@ -281,6 +281,8 @@ <h1>driver-wave</h1>
 <p>A runnable example that drives sixteen column heights from a custom function registered in <code>bpy.app.driver_namespace</code> — the pattern from <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/skills/drivers-and-app-handlers/SKILL.md"><code>drivers-and-app-handlers</code></a>. Each column gets a SCRIPTED driver on Z scale whose expression calls <code>wave_scale(i)</code>, producing a sine skyline.</p>
 <p><strong>What it witnesses:</strong> the driver evaluation contract. Driven values appear only after a view-layer update, and they land in <strong>two</strong> places that must agree: the depsgraph-evaluated copy (<code>evaluated_get(dg).scale</code>) and the original datablock, which the animation system flushes for display. The check asserts both against the closed-form profile.</p>
 <p>Note for real add-ons: <code>driver_namespace</code> entries do <strong>not</strong> persist in <code>.blend</code> files — re-register them from a <code>load_post</code> handler, or every driver that calls them fails on file open. Headless, registering before driver creation (as here) is enough.</p>
+<h2>Staging</h2>
+<p>The camera is raised to look down about 18 degrees, so the column tops and their shadows read as a wave. From nearly level (86 degrees) the skyline flattened into a bar chart. Render path only.</p>
 <h2>Run</h2>
 <pre><code># Cheap correctness check (no render) — the CI check:
 blender --background --python driver_wave.py --
@@ -457,8 +459,10 @@ <h2>Source</h2>
     <span class="c"># the frame with a small margin -- the skyline must not clip</span>
     cam_data = bpy.data.cameras.new(<span class="s">&quot;Cam&quot;</span>); cam_data.lens = <span class="n">42.0</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">15.0</span>, <span class="n">2.0</span>)
-    cam.rotation_euler = (math.radians(<span class="n">86</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
+    <span class="c"># raised so the column tops and their shadows read as a wave; from</span>
+    <span class="c"># nearly level (86 deg) it flattened into a bar chart</span>
+    cam.location = (<span class="n">0.0</span>, -<span class="n">14.2</span>, <span class="n">5.6</span>)
+    cam.rotation_euler = (math.radians(<span class="n">72</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
     scene.collection.objects.link(cam)
     scene.camera = cam
 
@@ -528,7 +532,7 @@ <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/driver-wave-hero.webp" alt="A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends." />
+    <img src="../assets/driver-wave-hero.webp" alt="A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the floor." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/hand-pump/index.html b/docs/gallery/hand-pump/index.html
index e58363ed..b6a921c4 100644
--- a/docs/gallery/hand-pump/index.html
+++ b/docs/gallery/hand-pump/index.html
@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/hand-pump-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth." />
+  <meta property="og:image:alt" content="A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="hand-pump — Showcase — Blender Developer Tools" />
   <meta name="twitter:description" content="A procedural village hand pump whose gooseneck is a 6-gon tube from the lower-column radius, 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/hand-pump-hero.webp" />
-  <meta name="twitter:image:alt" content="A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth." />
+  <meta name="twitter:image:alt" content="A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden 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>hand-pump</h1>
     <p>A procedural village hand pump whose gooseneck is a 6-gon tube from the lower-column radius, 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 dark iron village hand pump with a curved spout and lever handle on a square wooden plinth.">
-      <img src="../assets/hand-pump-hero.webp" alt="A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth.">
+      <img src="../assets/hand-pump-hero.webp" alt="A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth." 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: 1064 tris, two materials with 564 metal and 144 wood faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.610×0.382×1.052 m, grounded zmin, spout-to-column gap 2.7 mm, flange-to-plinth gap 6.0 mm, column radius 62 mm, LOD ratios in band, convex collider 114 tris, hygiene all zero, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z 16; --float-spout 17; --float-flange 18; --skinny-col 19.</div>
@@ -287,7 +287,9 @@ <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>900–2200</td><td>1064 / 1064 / 1064</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 / 0.2162</td></tr><tr><td>Materials</td><td>exactly 2 distinct, ≥48 metal, ≥24 wood</td><td>2 slots, 564 metal / 144 wood</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>(0.610, 0.382, 1.052) m ± 0.015</td><td>(0.6100, 0.3820, 1.0520), zmin 0</td></tr><tr><td>Collider tris</td><td>≤ 220</td><td>114</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>97304 / 97304 / 97296 bytes</td></tr></tbody></table></div>
 <p>Base triangles dropped from <strong>1164 to 1064</strong> in the quality pass: seven sausage cylinders became one gooseneck tube, and the wood grip is no longer beveled with the plinth. Outer AABB is 0.610 × 0.382 × 1.052 m (was 0.610 × 0.364 × 1.049 m).</p>
-<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — 5.2.1 is slightly 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. Construction uses no RNG. Export byte counts differ by 8 B on 5.2.1 (glTF serializer), not a gated axis.</p>
+<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — 5.2.1 is slightly 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. Construction is closed-form; the only RNG is the seeded per-piece wood tone. Bevel inputs are sorted by edge index, so the face order is the same on every run; a Python set of edges handed to the bevel had made it vary. Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis.</p>
+<h3>Surface and stage</h3>
+<p>The quality pass found no geometric defect: every joint checked in the inspection sheet (spout root, flange bolts, head and handle pivot, column step, plinth) seats as the joint budgets say. The defects were on the surface. The iron was polished metal (metallic 1.0, roughness 0.38) and read as chrome; it is now near-black painted cast iron with dark rust in the pores. The plinth slabs and the handle grip carry their own wood tone and grain. The stage grid grew from 14 to 60 m, because the wall&#x27;s left edge showed in the corner of the hero. The temp <code>.glb</code> is removed after its size is measured. With no new geometric defect, there is no new budget.</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>Plinth <code>zmin</code></td><td>within 1e-4 of 0</td><td>0.00000</td></tr></tbody></table></div>
@@ -333,7 +335,8 @@ <h2>Source</h2>
 ``--stray-vert``, ``--lift-z``, ``--float-spout``, ``--float-flange``,
 ``--skinny-col``.
 
-No RNG. Construction is closed-form. DECIMATE COLLAPSE triangle counts
+Construction is closed-form; the only RNG is the seeded per-piece wood
+tone. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
 ratio band, not an exact count.
 
@@ -344,6 +347,7 @@ <h2>Source</h2>
 <span class="k">import</span> argparse
 <span class="k">import</span> math
 <span class="k">import</span> os
+<span class="k">import</span> random
 <span class="k">import</span> sys
 <span class="k">import</span> tempfile
 <span class="k">import</span> traceback
@@ -405,6 +409,11 @@ <h2>Source</h2>
 WOOD_IDX = <span class="n">0</span>
 METAL_IDX = <span class="n">1</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>
+
 DOUBLES_EPS = <span class="n">1e-5</span>
 AREA_EPS = <span class="n">1e-10</span>
 ZMIN_EPS = <span class="n">1e-4</span>
@@ -715,6 +724,10 @@ <h2>Source</h2>
         )
         <span class="k">if</span> bevel_offset &gt; <span class="n">0.0</span>:
             edges = list({e <span class="k">for</span> v <span class="k">in</span> wood <span class="k">for</span> e <span class="k">in</span> v.link_edges})
+            <span class="c"># set order follows memory addresses; sort so the bevel, and the</span>
+            <span class="c"># face order it produces, are the same on every run</span>
+            bm.edges.index_update()
+            edges.sort(key=<span class="k">lambda</span> e: e.index)
             ret = bmesh.ops.bevel(
                 bm,
                 geom=edges,
@@ -890,6 +903,132 @@ <h2>Source</h2>
     <span class="k">return</span> mat
 
 
+<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.
+
+    Each plinth slab and the handle grip is its own shell, so each gets
+    one tone and grain running along its own long axis.
+    &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 slab and the grip (``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> pump_materials():
+    <span class="s">&quot;&quot;&quot;(wood, iron): shared by the check, the render and inspection.
+
+    A cast-iron pump is painted near-black and weathers to rust at the
+    edges and pores; the first build was polished metal (metallic 1.0,
+    roughness 0.38) and read as chrome.
+    &quot;&quot;&quot;</span>
+    wood = wood_material(<span class="s">&quot;HandPumpWood&quot;</span>)
+    metal = principled(
+        <span class="s">&quot;HandPumpIron&quot;</span>, (<span class="n">0.045</span>, <span class="n">0.047</span>, <span class="n">0.050</span>, <span class="n">1.0</span>), <span class="n">0.55</span>, <span class="n">0.52</span>,
+        noise_scale=<span class="n">24.0</span>, wear=(<span class="n">0.09</span>, <span class="n">0.05</span>, <span class="n">0.03</span>, <span class="n">1.0</span>),
+    )
+    <span class="k">return</span> wood, metal
+
+
 <span class="k">def</span> assign_slots(obj, wood, metal):
     mats = obj.data.materials
     wanted = (wood, metal)
@@ -1220,14 +1359,9 @@ <h2>Source</h2>
     )
     low = build_hand_pump_mesh(<span class="s">&quot;HandPumpLow&quot;</span>, bevel_offset=<span class="n">0.004</span>, bevel_segments=<span class="n">2</span>, **kw)
     high = build_hand_pump_mesh(<span class="s">&quot;HandPumpHigh&quot;</span>, bevel_offset=<span class="n">0.004</span>, bevel_segments=<span class="n">4</span>, **kw)
-    wood = principled(
-        <span class="s">&quot;HandPumpWood&quot;</span>, (<span class="n">0.36</span>, <span class="n">0.19</span>, <span class="n">0.07</span>, <span class="n">1.0</span>), <span class="n">0.0</span>, <span class="n">0.60</span>,
-        noise_scale=<span class="n">14.0</span>, wear=(<span class="n">0.22</span>, <span class="n">0.12</span>, <span class="n">0.05</span>, <span class="n">1.0</span>),
-    )
-    metal = principled(
-        <span class="s">&quot;HandPumpIron&quot;</span>, (<span class="n">0.18</span>, <span class="n">0.175</span>, <span class="n">0.17</span>, <span class="n">1.0</span>), <span class="n">1.0</span>, <span class="n">0.38</span>,
-        noise_scale=<span class="n">18.0</span>, wear=(<span class="n">0.28</span>, <span class="n">0.24</span>, <span class="n">0.18</span>, <span class="n">1.0</span>),
-    )
+    wood, metal = pump_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
 
@@ -1283,6 +1417,10 @@ <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)
 
     hyg = hygiene_audit(low.data)
     zf = zfight_pairs(low.data)
@@ -1438,7 +1576,9 @@ <h2>Source</h2>
     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">14.0</span>)
+        <span class="c"># Oversized so no edge of the set can enter frame; at 14 m the wall&#x27;s</span>
+        <span class="c"># left edge showed as a bright band in the corner of the hero.</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()
@@ -1564,7 +1704,7 @@ <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/hand-pump-hero.webp" alt="A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth." />
+    <img src="../assets/hand-pump-hero.webp" alt="A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/hitching-post/index.html b/docs/gallery/hitching-post/index.html
index 2f89b2ff..6a144f11 100644
--- a/docs/gallery/hitching-post/index.html
+++ b/docs/gallery/hitching-post/index.html
@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/hitching-post-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="A tall wooden hitching post with a pointed cap, a crossbar and two iron rings." />
+  <meta property="og:image:alt" content="A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="hitching-post — Showcase — Blender Developer Tools" />
   <meta name="twitter:description" content="A procedural hitching post (eaved cap, one rail, cup shoe, rings hung through eyes) 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/hitching-post-hero.webp" />
-  <meta name="twitter:image:alt" content="A tall wooden hitching post with a pointed cap, a crossbar and two iron rings." />
+  <meta name="twitter:image:alt" content="A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings." />
   <style>
     /* fonts are deployed by the landing build (docs/fonts/) */
     @font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
@@ -268,11 +268,11 @@ <h1>hitching-post</h1>
     <p>A procedural hitching post (eaved cap, one rail, cup shoe, rings hung through eyes) 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 tall wooden hitching post with a pointed cap, a crossbar and two iron rings.">
-      <img src="../assets/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar and two iron rings." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings.">
+      <img src="../assets/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron 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: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring exits 18; --short-post exits 19.</div>
+    <div class="callout"><span class="tag">witnesses</span> Recomputed: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, bands 6.5 mm proud of the post, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring and --sunk-bands exit 18; --short-post exits 19.</div>
     <div class="runline">
       <pre id="runCmd">blender --background --python showcase/hitching-post/hitching_post.py --</pre>
       <button class="copy-btn" id="copyRun" type="button">Copy</button>
@@ -284,11 +284,14 @@ <h1>hitching-post</h1>
 <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). Hygiene combinatorics match <code>examples/mesh-hygiene-audit</code> (copied, not imported). Coplanar-pair counting matches <code>showcase/signpost</code>.</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>1400–2400</td><td>1680 / 1680 / 1680</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>0.2190 / 0.2190 / 0.2190</td></tr><tr><td>Materials</td><td>exactly 2 distinct, ≥70 wood, ≥560 metal</td><td>2 slots, 114 wood, 742 metal</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>(0.500, 0.149, 1.246) m ± 0.01</td><td>(0.5000, 0.1490, 1.2460)</td></tr><tr><td>Grounded zmin</td><td>within 1e-4 of 0</td><td>0 / 0 / 0</td></tr><tr><td>Hygiene</td><td>loose/nonman/zero-area/doubles/n-gons/coplanar pairs = 0</td><td>all 0</td></tr><tr><td>Post seat</td><td>world zmin in (0.004, 0.014), XY centroid within 0.010 of origin, arm axis cos ≥ cos(0.5°)</td><td>0.01000, 0, 1.000</td></tr><tr><td>Hung ring</td><td>centerline error ≤ 0.008 m, ring–wood overlap 0, eye–wood overlap 0, shank–ring overlap 0, shank bites the eye</td><td>0, 0, 0, 0, 40</td></tr><tr><td>Shoe</td><td>each band overlaps the post, shoe overlaps the sole</td><td>band gap 0, sole–shoe 8</td></tr><tr><td>Wood–metal gap</td><td>BVH surface &lt; 0.008 m</td><td>0.00075</td></tr><tr><td>Collider tris</td><td>≤ 280</td><td>80</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>127428 / 127428 / 127412 bytes</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 (4.5.11 / 5.1.2 / 5.2.1)</th></tr></thead><tbody><tr><td>Base triangles</td><td>1400–2400</td><td>1680 / 1680 / 1680</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>0.2190 / 0.2190 / 0.2190</td></tr><tr><td>Materials</td><td>exactly 2 distinct, ≥70 wood, ≥560 metal</td><td>2 slots, 114 wood, 742 metal</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>(0.500, 0.149, 1.246) m ± 0.01</td><td>(0.5000, 0.1490, 1.2460)</td></tr><tr><td>Grounded zmin</td><td>within 1e-4 of 0</td><td>0 / 0 / 0</td></tr><tr><td>Hygiene</td><td>loose/nonman/zero-area/doubles/n-gons/coplanar pairs = 0</td><td>all 0</td></tr><tr><td>Post seat</td><td>world zmin in (0.004, 0.014), XY centroid within 0.010 of origin, arm axis cos ≥ cos(0.5°)</td><td>0.01000, 0, 1.000</td></tr><tr><td>Hung ring</td><td>centerline error ≤ 0.008 m, ring–wood overlap 0, eye–wood overlap 0, shank–ring overlap 0, shank bites the eye</td><td>0, 0, 0, 0, 40</td></tr><tr><td>Shoe</td><td>each band overlaps the post, shoe overlaps the sole</td><td>band gap 0, sole–shoe 8</td></tr><tr><td><strong>Band seat</strong></td><td>each band above the shoe stands ≥ 0.004 m proud of the post faces</td><td>0.00650</td></tr><tr><td>Wood–metal gap</td><td>BVH surface &lt; 0.008 m</td><td>0.00075</td></tr><tr><td>Collider tris</td><td>≤ 280</td><td>80</td></tr><tr><td>Export</td><td>written, size &gt; 0</td><td>127424 / 127424 / 127412 bytes</td></tr></tbody></table></div>
 <p>Base triangles rose from <strong>1598 to 1680</strong>. The old rings were faceted tori clipped into the arm; the new eyes, shanks, and 24-segment hung rings replace that mesh. Cylinder caps are triangulated so the n-gon budget stays at 0.</p>
-<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — the gate is a ratio band, not an exact count. On this mesh the three binaries agreed. Bake pixels are stochastic; the gate is <code>has_data</code> plus operator <code>FINISHED</code>, not byte-identity. Construction uses no RNG. Export byte counts differ by 16 B on 5.2.1 (glTF serializer), not a gated axis. Euler is 12 (six balls and seven tori) and is not gated to 2.</p>
+<p>DECIMATE COLLAPSE triangle counts are <strong>not</strong> identical across series — the gate is a ratio band, not an exact count. On this mesh the three binaries agreed. Bake pixels are stochastic; the gate is <code>has_data</code> plus operator <code>FINISHED</code>, not byte-identity. Construction is closed-form; the only RNG is the seeded per-piece wood tone. Bevel inputs are sorted by edge index, so the face order is the same on every run; a Python set of edges handed to the bevel had made it vary. Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis. Euler is 12 (six balls and seven tori) and is not gated to 2.</p>
+<h3>Bands, wood and stage</h3>
+<p>The two iron bands were sized from <code>half - grip</code>: an inner half-width of 53 mm and an outer one of 61 mm, against a 62.5 mm post face. They sat inside the post, and only the chamfered corners broke the surface, showing as small black slits up the post. They now wrap it: the inner face bites 1.5 mm into the post (<code>BAND_BITE</code>), so each band stands 6.5 mm proud. <strong>Band seat</strong> asserts it; <code>--sunk-bands</code> restores the old bands and exits 18 (proud −0.0015 m).</p>
+<p>The post, rail and cap each carry their own tone and grain, and the iron is rusted. The stage grid grew from 14 to 60 m, because the wall&#x27;s left edge showed as a bright band in the corner of the hero. The temp <code>.glb</code> is removed after its size is measured.</p>
 <p>Each falsifier violates exactly one named budget. Proven on Blender 4.5.11 LTS, 5.1.2, and 5.2.1 LTS (the binaries&#x27; own <code>--version</code>):</p>
-<div class="table-wrap"><table><thead><tr><th scope="col">Falsifier</th><th scope="col">Budget violated</th><th scope="col">Exit</th><th scope="col">Measured failure</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td><td>ratio 1.0000</td></tr><tr><td><code>--stray-vert</code></td><td>Mesh hygiene, loose verts</td><td>15</td><td><code>loose_v=1</code></td></tr><tr><td><code>--twin-sole</code></td><td>Coplanar face pairs</td><td>15</td><td><code>zfight=6</code></td></tr><tr><td><code>--lift-z</code></td><td>Grounded zmin</td><td>16</td><td>zmin 0.050000</td></tr><tr><td><code>--clip-ring</code></td><td>Hung-ring centerline</td><td>18</td><td>ring_err 0.024, ring–wood overlap 32</td></tr><tr><td><code>--short-post</code></td><td>Seated post</td><td>19</td><td>post zmin 0.030</td></tr></tbody></table></div>
+<div class="table-wrap"><table><thead><tr><th scope="col">Falsifier</th><th scope="col">Budget violated</th><th scope="col">Exit</th><th scope="col">Measured failure</th></tr></thead><tbody><tr><td><code>--skip-decimate</code></td><td>LOD1 ratio band</td><td>9</td><td>ratio 1.0000</td></tr><tr><td><code>--stray-vert</code></td><td>Mesh hygiene, loose verts</td><td>15</td><td><code>loose_v=1</code></td></tr><tr><td><code>--twin-sole</code></td><td>Coplanar face pairs</td><td>15</td><td><code>zfight=6</code></td></tr><tr><td><code>--lift-z</code></td><td>Grounded zmin</td><td>16</td><td>zmin 0.050000</td></tr><tr><td><code>--clip-ring</code></td><td>Hung-ring centerline</td><td>18</td><td>ring_err 0.024, ring–wood overlap 32</td></tr><tr><td><code>--short-post</code></td><td>Seated post</td><td>19</td><td>post zmin 0.030</td></tr><tr><td><code>--sunk-bands</code></td><td>Band seat</td><td>18</td><td>band proud −0.0015</td></tr></tbody></table></div>
 <p>Default exit is 0 on all three. <code>--clip-ring</code> also overlaps the rail; the centerline gate is the one that fires.</p>
 <h2>Run</h2>
 <pre><code>blender --background --python hitching_post.py --
@@ -298,11 +301,12 @@ <h2>Run</h2>
 blender --background --python hitching_post.py -- --lift-z
 blender --background --python hitching_post.py -- --clip-ring
 blender --background --python hitching_post.py -- --short-post
+blender --background --python hitching_post.py -- --sunk-bands
 blender --background --python hitching_post.py -- --output preview.webp --engine cycles</code></pre>
 <p>Smoke does not pass <code>--output</code> or a falsifier.</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.</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 wood/metal faces missing</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>Hygiene, including coplanar pairs (<code>--stray-vert</code>, <code>--twin-sole</code>)</td></tr><tr><td>16</td><td>Grounded zmin (<code>--lift-z</code>)</td></tr><tr><td>17</td><td>Wood–metal BVH gap above 8 mm</td></tr><tr><td>18</td><td>Hung ring or shoe seat (<code>--clip-ring</code>)</td></tr><tr><td>19</td><td>Post plumb, origin, and cup seat (<code>--short-post</code>)</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 wood/metal faces missing</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>Hygiene, including coplanar pairs (<code>--stray-vert</code>, <code>--twin-sole</code>)</td></tr><tr><td>16</td><td>Grounded zmin (<code>--lift-z</code>)</td></tr><tr><td>17</td><td>Wood–metal BVH gap above 8 mm</td></tr><tr><td>18</td><td>Hung ring, shoe or band seat (<code>--clip-ring</code>, <code>--sunk-bands</code>)</td></tr><tr><td>19</td><td>Post plumb, origin, and cup seat (<code>--short-post</code>)</td></tr></tbody></table></div>
     </section>
     <section class="detail-section src">
       <h2>Source</h2>
@@ -325,9 +329,12 @@ <h2>Source</h2>
 vertex so the hygiene budget fails. ``--twin-sole`` duplicates the shoe
 plate so the coplanar-face budget fails. ``--clip-ring`` lifts a hung
 ring off the eye centerline. ``--short-post`` starts the post above the
-shoe cup so the seated-post budget fails.
+shoe cup so the seated-post budget fails. ``--sunk-bands`` builds the
+iron bands inside the post, as the piece first shipped, so the band-seat
+budget fails.
 
-No RNG. Construction is closed-form. DECIMATE COLLAPSE triangle counts
+Construction is closed-form; the only RNG is the seeded per-piece wood
+tone. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
 ratio band, not an exact count.
 
@@ -338,11 +345,13 @@ <h2>Source</h2>
     blender --background --python hitching_post.py -- --twin-sole
     blender --background --python hitching_post.py -- --clip-ring
     blender --background --python hitching_post.py -- --short-post
+    blender --background --python hitching_post.py -- --sunk-bands
     blender --background --python hitching_post.py -- --output hitching-post.png
 &quot;&quot;&quot;</span>
 <span class="k">import</span> argparse
 <span class="k">import</span> math
 <span class="k">import</span> os
+<span class="k">import</span> random
 <span class="k">import</span> sys
 <span class="k">import</span> tempfile
 <span class="k">import</span> traceback
@@ -380,6 +389,16 @@ <h2>Source</h2>
 BAND_H = <span class="n">0.026</span>
 BAND_T = <span class="n">0.008</span>
 BAND_ZS = (<span class="n">0.24</span>, <span class="n">0.56</span>)
+<span class="c"># Bands wrap the post: inner face BAND_BITE inside the post face, so each</span>
+<span class="c"># band stands BAND_T - BAND_BITE proud. The first build sized them from</span>
+<span class="c"># ``half - grip`` and sank them inside the post, so only the chamfered</span>
+<span class="c"># corners broke the surface, as black slits. --sunk-bands restores that.</span>
+BAND_BITE = <span class="n">0.0015</span>
+BAND_PROUD_MIN = <span class="n">0.004</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="c"># Ring tube must fit through the eye: RING_MINOR &lt; EYE_MAJOR - EYE_MINOR.</span>
 RING_FIT = <span class="n">0.004</span>
 POST_ZMIN_LO = <span class="n">0.004</span>
@@ -781,6 +800,7 @@ <h2>Source</h2>
         <span class="s">&quot;shanks&quot;</span>: <span class="n">0</span>,
         <span class="s">&quot;shank_ring&quot;</span>: <span class="n">99</span>,
         <span class="s">&quot;shank_eye&quot;</span>: <span class="n">0</span>,
+        <span class="s">&quot;band_proud&quot;</span>: -<span class="n">1.0</span>,
     }
     <span class="k">if</span> (
         post <span class="k">is</span> <span class="k">None</span>
@@ -829,6 +849,17 @@ <h2>Source</h2>
     shoe = min(bands, key=<span class="k">lambda</span> b: b[<span class="s">&quot;z0&quot;</span>])
     sole_shoe = len(_bvh(me, soles[<span class="n">0</span>][<span class="s">&quot;polys&quot;</span>]).overlap(_bvh(me, shoe[<span class="s">&quot;polys&quot;</span>])))
 
+    <span class="c"># Each band above the shoe must stand proud of the post faces: its</span>
+    <span class="c"># outer half-width in plan against the post&#x27;s.</span>
+    post_x0, post_x1, post_y0, post_y1, _pz0, _pz1 = _bounds(me, post[<span class="s">&quot;idxs&quot;</span>])
+    post_half = <span class="n">0.25</span> * ((post_x1 - post_x0) + (post_y1 - post_y0))
+    band_proud = <span class="n">99.0</span>
+    <span class="k">for</span> band <span class="k">in</span> bands:
+        <span class="k">if</span> band <span class="k">is</span> shoe:
+            <span class="k">continue</span>
+        bx0, bx1, by0, by1, _bz0, _bz1 = _bounds(me, band[<span class="s">&quot;idxs&quot;</span>])
+        band_proud = min(band_proud, <span class="n">0.25</span> * ((bx1 - bx0) + (by1 - by0)) - post_half)
+
     pos, neg = [], []
     <span class="k">for</span> i <span class="k">in</span> arm[<span class="s">&quot;idxs&quot;</span>]:
         co = me.vertices[i].co
@@ -855,6 +886,7 @@ <h2>Source</h2>
         <span class="s">&quot;shanks&quot;</span>: len(shanks),
         <span class="s">&quot;shank_ring&quot;</span>: shank_ring,
         <span class="s">&quot;shank_eye&quot;</span>: shank_eye,
+        <span class="s">&quot;band_proud&quot;</span>: band_proud,
     })
     <span class="k">return</span> out
 
@@ -986,6 +1018,7 @@ <h2>Source</h2>
     clip_ring=<span class="k">False</span>,
     twin_sole=<span class="k">False</span>,
     small_cap=<span class="k">False</span>,
+    sunk_bands=<span class="k">False</span>,
 ):
     <span class="s">&quot;&quot;&quot;Post on a closed shoe, one rail, rings hung through eyes under the rail.
 
@@ -1016,6 +1049,10 @@ <h2>Source</h2>
         )
         <span class="k">if</span> bevel_offset &gt; <span class="n">0.0</span>:
             edges = list({e <span class="k">for</span> v <span class="k">in</span> wood <span class="k">for</span> e <span class="k">in</span> v.link_edges <span class="k">if</span> v.is_valid})
+            <span class="c"># set order follows memory addresses; sort so the bevel, and the</span>
+            <span class="c"># face order it produces, are the same on every run</span>
+            bm.edges.index_update()
+            edges.sort(key=<span class="k">lambda</span> e: e.index)
             ret = bmesh.ops.bevel(
                 bm,
                 geom=edges,
@@ -1065,8 +1102,9 @@ <h2>Source</h2>
             wall_z1 - wall_z0,
             METAL_IDX,
         )
+        band_in = (half - grip) <span class="k">if</span> sunk_bands <span class="k">else</span> (half - BAND_BITE)
         <span class="k">for</span> z <span class="k">in</span> BAND_ZS:
-            add_square_band(bm, z, half - grip, BAND_T, BAND_H, METAL_IDX)
+            add_square_band(bm, z, band_in, BAND_T, BAND_H, METAL_IDX)
 
         arm_bottom = ARM_Z - ARM_ZTH * <span class="n">0.5</span>
         eye_z = arm_bottom - EYE_MAJOR - EYE_MINOR - <span class="n">0.004</span>
@@ -1155,6 +1193,127 @@ <h2>Source</h2>
     <span class="k">return</span> mat
 
 
+<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.
+
+    The post, the rail and the cap are each their own shell, so each gets
+    one tone and grain running along its own long axis.
+    &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, _polys <span class="k">in</span> _face_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 the post and rail (``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> post_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;HitchPostWood&quot;</span>)
+    metal = principled(
+        <span class="s">&quot;HitchPostIron&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> assign_slots(obj, wood, metal):
     mats = obj.data.materials
     wanted = (wood, metal)
@@ -1291,6 +1450,7 @@ <h2>Source</h2>
     twin_sole=<span class="k">False</span>,
     clip_ring=<span class="k">False</span>,
     short_post=<span class="k">False</span>,
+    sunk_bands=<span class="k">False</span>,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=<span class="k">True</span>)
     low = build_hitching_post_mesh(
@@ -1300,24 +1460,14 @@ <h2>Source</h2>
         short_post=short_post,
         clip_ring=clip_ring,
         twin_sole=twin_sole,
+        sunk_bands=sunk_bands,
     )
-    high = build_hitching_post_mesh(<span class="s">&quot;HitchPostHigh&quot;</span>, bevel_offset=<span class="n">0.008</span>, bevel_segments=<span class="n">4</span>)
-    wood = principled(
-        <span class="s">&quot;HitchPostWood&quot;</span>,
-        (<span class="n">0.36</span>, <span class="n">0.19</span>, <span class="n">0.07</span>, <span class="n">1.0</span>),
-        <span class="n">0.0</span>,
-        <span class="n">0.62</span>,
-        noise_scale=<span class="n">11.0</span>,
-        wear=(<span class="n">0.24</span>, <span class="n">0.13</span>, <span class="n">0.05</span>, <span class="n">1.0</span>),
-    )
-    metal = principled(
-        <span class="s">&quot;HitchPostIron&quot;</span>,
-        (<span class="n">0.16</span>, <span class="n">0.155</span>, <span class="n">0.15</span>, <span class="n">1.0</span>),
-        <span class="n">1.0</span>,
-        <span class="n">0.48</span>,
-        noise_scale=<span class="n">16.0</span>,
-        wear=(<span class="n">0.09</span>, <span class="n">0.085</span>, <span class="n">0.08</span>, <span class="n">1.0</span>),
+    high = build_hitching_post_mesh(
+        <span class="s">&quot;HitchPostHigh&quot;</span>, bevel_offset=<span class="n">0.008</span>, bevel_segments=<span class="n">4</span>, sunk_bands=sunk_bands,
     )
+    wood, metal = post_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
     <span class="k">if</span> lift_z:
@@ -1372,6 +1522,10 @@ <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(
@@ -1408,7 +1562,8 @@ <h2>Source</h2>
         <span class="s">f&quot;</span><span class="s">band_gap=</span>{seat[<span class="s">&#x27;band_gap&#x27;</span>]:<span class="s">.5f</span>}<span class="s"> sole_shoe=</span>{seat[<span class="s">&#x27;sole_shoe&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
         <span class="s">f&quot;</span><span class="s">shank_ring=</span>{seat[<span class="s">&#x27;shank_ring&#x27;</span>]}<span class="s"> shank_eye=</span>{seat[<span class="s">&#x27;shank_eye&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
         <span class="s">f&quot;</span><span class="s">parts=</span>{seat[<span class="s">&#x27;post&#x27;</span>]}<span class="s">/</span>{seat[<span class="s">&#x27;arm&#x27;</span>]}<span class="s">/</span>{seat[<span class="s">&#x27;cap&#x27;</span>]}<span class="s">/</span><span class="s">&quot;</span>
-        <span class="s">f&quot;</span><span class="s">soles=</span>{seat[<span class="s">&#x27;soles&#x27;</span>]}<span class="s">/rings=</span>{seat[<span class="s">&#x27;rings&#x27;</span>]}<span class="s">/eyes=</span>{seat[<span class="s">&#x27;eyes&#x27;</span>]}<span class="s">/bands=</span>{seat[<span class="s">&#x27;bands&#x27;</span>]}<span class="s">&quot;</span>
+        <span class="s">f&quot;</span><span class="s">soles=</span>{seat[<span class="s">&#x27;soles&#x27;</span>]}<span class="s">/rings=</span>{seat[<span class="s">&#x27;rings&#x27;</span>]}<span class="s">/eyes=</span>{seat[<span class="s">&#x27;eyes&#x27;</span>]}<span class="s">/bands=</span>{seat[<span class="s">&#x27;bands&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
+        <span class="s">f&quot;</span><span class="s">band_proud=</span>{seat[<span class="s">&#x27;band_proud&#x27;</span>]:<span class="s">.5f</span>}<span class="s">&quot;</span>
     )
 
     <span class="k">if</span> <span class="k">not</span> (BASE_TRIS_MIN &lt;= base_tris &lt;= BASE_TRIS_MAX):
@@ -1514,13 +1669,15 @@ <h2>Source</h2>
         <span class="k">or</span> seat[<span class="s">&quot;sole_shoe&quot;</span>] &lt; <span class="n">1</span>
         <span class="k">or</span> seat[<span class="s">&quot;shank_ring&quot;</span>]
         <span class="k">or</span> seat[<span class="s">&quot;shank_eye&quot;</span>] &lt; <span class="n">1</span>
+        <span class="k">or</span> seat[<span class="s">&quot;band_proud&quot;</span>] &lt; BAND_PROUD_MIN
     ):
         <span class="k">return</span> fail(
             <span class="s">f&quot;</span><span class="s">hung ring / shoe seat ring_err=</span>{seat[<span class="s">&#x27;ring_err&#x27;</span>]:<span class="s">.5f</span>}<span class="s"> </span><span class="s">&quot;</span>
             <span class="s">f&quot;</span><span class="s">ring_wood=</span>{seat[<span class="s">&#x27;ring_wood&#x27;</span>]}<span class="s"> eye_wood=</span>{seat[<span class="s">&#x27;eye_wood&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
             <span class="s">f&quot;</span><span class="s">band_gap=</span>{seat[<span class="s">&#x27;band_gap&#x27;</span>]:<span class="s">.5f</span>}<span class="s"> sole_shoe=</span>{seat[<span class="s">&#x27;sole_shoe&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
             <span class="s">f&quot;</span><span class="s">shank_ring=</span>{seat[<span class="s">&#x27;shank_ring&#x27;</span>]}<span class="s"> shank_eye=</span>{seat[<span class="s">&#x27;shank_eye&#x27;</span>]}<span class="s"> </span><span class="s">&quot;</span>
-            <span class="s">&quot;(--clip-ring is the designed fail)&quot;</span>,
+            <span class="s">f&quot;</span><span class="s">band_proud=</span>{seat[<span class="s">&#x27;band_proud&#x27;</span>]:<span class="s">.5f</span>}<span class="s"> (min </span>{BAND_PROUD_MIN}<span class="s">) </span><span class="s">&quot;</span>
+            <span class="s">&quot;(--clip-ring / --sunk-bands are the designed fails)&quot;</span>,
             <span class="n">18</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> (
@@ -1560,7 +1717,9 @@ <h2>Source</h2>
     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">14.0</span>)
+        <span class="c"># Oversized so no edge of the set can enter frame; at 14 m the wall&#x27;s</span>
+        <span class="c"># left edge showed as a bright band in the corner of the hero.</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()
@@ -1677,6 +1836,11 @@ <h2>Source</h2>
         action=<span class="s">&quot;store_true&quot;</span>,
         help=<span class="s">&quot;falsification: start the post above the shoe cup&quot;</span>,
     )
+    p.add_argument(
+        <span class="s">&quot;--sunk-bands&quot;</span>,
+        action=<span class="s">&quot;store_true&quot;</span>,
+        help=<span class="s">&quot;falsification: bands inside the post, only the corners showing&quot;</span>,
+    )
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1686,6 +1850,7 @@ <h2>Source</h2>
         twin_sole=args.twin_sole,
         clip_ring=args.clip_ring,
         short_post=args.short_post,
+        sunk_bands=args.sunk_bands,
     )
     <span class="k">if</span> code:
         <span class="k">return</span> code
@@ -1710,7 +1875,7 @@ <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/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar and two iron rings." />
+    <img src="../assets/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings." />
   </dialog>
   <footer>
     <div class="statusbar">
diff --git a/docs/gallery/index.html b/docs/gallery/index.html
index 8f03dcc9..2c04f54a 100644
--- a/docs/gallery/index.html
+++ b/docs/gallery/index.html
@@ -398,7 +398,7 @@ <h2><a href="wave-displace/">wave-displace</a></h2>
       </article>
       <article class="card" data-tags="drivers animation">
         <a class="card-media" href="driver-wave/" tabindex="-1" aria-hidden="true">
-          <img src="assets/driver-wave-hero.webp" alt="A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends." loading="lazy" decoding="async" />
+          <img src="assets/driver-wave-hero.webp" alt="A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the floor." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="driver-wave/">driver-wave</a></h2>
@@ -1069,12 +1069,12 @@ <h2><a href="water-trough/">water-trough</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="hitching-post/" tabindex="-1" aria-hidden="true">
-          <img src="assets/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar and two iron rings." loading="lazy" decoding="async" />
+          <img src="assets/hitching-post-hero.webp" alt="A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="hitching-post/">hitching-post</a></h2>
           <p class="teaches">A procedural hitching post (eaved cap, one rail, cup shoe, rings hung through eyes) 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: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring exits 18; --short-post exits 19.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, bands 6.5 mm proud of the post, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring and --sunk-bands exit 18; --short-post exits 19.</p>
           <a class="card-link" href="hitching-post/">View showcase piece<span class="sr-only"> hitching-post</span> <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
@@ -1091,7 +1091,7 @@ <h2><a href="grindstone/">grindstone</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="hand-pump/" tabindex="-1" aria-hidden="true">
-          <img src="assets/hand-pump-hero.webp" alt="A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth." loading="lazy" decoding="async" />
+          <img src="assets/hand-pump-hero.webp" alt="A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="hand-pump/">hand-pump</a></h2>
diff --git a/docs/gallery/shader-node-group/index.html b/docs/gallery/shader-node-group/index.html
index 0955a70d..52c47531 100644
--- a/docs/gallery/shader-node-group/index.html
+++ b/docs/gallery/shader-node-group/index.html
@@ -280,6 +280,8 @@ <h1>shader-node-group</h1>
     <section class="detail-section md">
 <p>A runnable example that declares a reusable <code>TintedGloss</code> shader group through <code>tree.interface.new_socket</code> — the 4.x/5.x API that replaced <code>tree.inputs</code>/<code>tree.outputs</code> — and instances it in two materials with different parameters, following <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/skills/procedural-materials-and-shaders/SKILL.md"><code>procedural-materials-and-shaders</code></a> and the <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/snippets/shader-node-group.py"><code>shader-node-group</code></a> snippet.</p>
 <p><strong>What it witnesses:</strong> the grouping contract. Sockets declared on the interface appear on every group-node instance; both materials share ONE group datablock (<code>users == 2</code>); and the per-material Tint lives on the group <strong>node</strong>, not inside the group — set it inside the tree and every material changes at once. The render is the proof: two spheres, one group, two colors.</p>
+<h2>Staging</h2>
+<p>The still renders under the Standard view transform on the dark house stage; it had no view transform set, so AgX washed both tints toward pastel over a lighter floor. The key is larger and softer (the glossy spheres had mirrored it as a hard white square), and the camera aims at the sphere centres. Render path only.</p>
 <h2>Run</h2>
 <pre><code># Cheap correctness check (no render) — the CI check:
 blender --background --python shader_node_group.py --
@@ -438,8 +440,8 @@ <h2>Source</h2>
     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">0.055</span>, <span class="n">0.06</span>, <span class="n">0.07</span>, <span class="n">1.0</span>)
-    fb.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.5</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)
@@ -450,7 +452,7 @@ <h2>Source</h2>
 
     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="k">def</span> light(name, loc, energy, size, col, rot):
@@ -461,16 +463,26 @@ <h2>Source</h2>
         ob.rotation_euler = tuple(math.radians(a) <span class="k">for</span> a <span class="k">in</span> rot)
         scene.collection.objects.link(ob)
 
-    light(<span class="s">&quot;Key&quot;</span>, (-<span class="n">4.0</span>, -<span class="n">5.0</span>, <span class="n">6.5</span>), <span class="n">1400.0</span>, <span class="n">5.5</span>, (<span class="n">1.0</span>, <span class="n">0.98</span>, <span class="n">0.94</span>), (<span class="n">46</span>, <span class="n">0</span>, -<span class="n">35</span>))
+    <span class="c"># a large soft key: at 5.5 m the glossy spheres mirrored it as a hard</span>
+    <span class="c"># white square</span>
+    light(<span class="s">&quot;Key&quot;</span>, (-<span class="n">4.0</span>, -<span class="n">5.0</span>, <span class="n">6.5</span>), <span class="n">1100.0</span>, <span class="n">9.0</span>, (<span class="n">1.0</span>, <span class="n">0.98</span>, <span class="n">0.94</span>), (<span class="n">46</span>, <span class="n">0</span>, -<span class="n">35</span>))
     light(<span class="s">&quot;Fill&quot;</span>, (<span class="n">5.5</span>, -<span class="n">4.0</span>, <span class="n">3.0</span>), <span class="n">280.0</span>, <span class="n">8.0</span>, (<span class="n">0.82</span>, <span class="n">0.88</span>, <span class="n">1.0</span>), (<span class="n">63</span>, <span class="n">0</span>, <span class="n">48</span>))
     light(<span class="s">&quot;Rim&quot;</span>, (<span class="n">0.5</span>, <span class="n">6.0</span>, <span class="n">4.0</span>), <span class="n">900.0</span>, <span class="n">3.5</span>, (<span class="n">1.0</span>, <span class="n">0.74</span>, <span class="n">0.46</span>), (-<span class="n">62</span>, <span class="n">0</span>, <span class="n">175</span>))
 
     cam_data = bpy.data.cameras.new(<span class="s">&quot;Cam&quot;</span>)
-    cam_data.lens = <span class="n">58.0</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">8.7</span>, <span class="n">2.6</span>)
-    cam.rotation_euler = (math.radians(<span class="n">78</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
+    cam.location = (<span class="n">0.0</span>, -<span class="n">8.4</span>, <span class="n">3.3</span>)
     scene.collection.objects.link(cam)
+    <span class="c"># aim at the spheres&#x27; centres so they sit mid-frame, not above a band of</span>
+    <span class="c"># empty floor</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">0.0</span>, <span class="n">1.0</span>)
+    scene.collection.objects.link(aim)
+    track = cam.constraints.new(<span class="s">&#x27;TRACK_TO&#x27;</span>)
+    track.target = aim
+    track.track_axis = <span class="s">&#x27;TRACK_NEGATIVE_Z&#x27;</span>
+    track.up_axis = <span class="s">&#x27;UP_Y&#x27;</span>
     scene.camera = cam
 
     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()
@@ -485,6 +497,8 @@ <h2>Source</h2>
     scene.render.resolution_y = <span class="n">720</span>
     scene.render.image_settings.file_format = <span class="s">&#x27;PNG&#x27;</span>
     scene.render.filepath = path
+    <span class="c"># AgX would wash both tints toward pastel (docs/VISUAL-STYLE.md)</span>
+    scene.view_settings.view_transform = <span class="s">&#x27;Standard&#x27;</span>
     <span class="c"># Layer 1 framing gate (silhouette matte) — exit 10 on violation, before</span>
     <span class="c"># the beauty render so a defective composition ships no artifact.</span>
     fcode = gallery_framing.check_framing(
diff --git a/examples/driver-wave/README.md b/examples/driver-wave/README.md
index b7bc6f1b..e73d9813 100644
--- a/examples/driver-wave/README.md
+++ b/examples/driver-wave/README.md
@@ -15,6 +15,12 @@ Note for real add-ons: `driver_namespace` entries do **not** persist in `.blend`
 re-register them from a `load_post` handler, or every driver that calls them fails on file
 open. Headless, registering before driver creation (as here) is enough.
 
+## Staging
+
+The camera is raised to look down about 18 degrees, so the column tops
+and their shadows read as a wave. From nearly level (86 degrees) the
+skyline flattened into a bar chart. Render path only.
+
 ## Run
 
 ```bash
diff --git a/examples/driver-wave/driver_wave.py b/examples/driver-wave/driver_wave.py
index e6b5b7f3..38973fd5 100644
--- a/examples/driver-wave/driver_wave.py
+++ b/examples/driver-wave/driver_wave.py
@@ -153,8 +153,10 @@ def render_still(objs, path, engine):
     # the frame with a small margin -- the skyline must not clip
     cam_data = bpy.data.cameras.new("Cam"); cam_data.lens = 42.0
     cam = bpy.data.objects.new("Cam", cam_data)
-    cam.location = (0.0, -15.0, 2.0)
-    cam.rotation_euler = (math.radians(86), 0.0, 0.0)
+    # raised so the column tops and their shadows read as a wave; from
+    # nearly level (86 deg) it flattened into a bar chart
+    cam.location = (0.0, -14.2, 5.6)
+    cam.rotation_euler = (math.radians(72), 0.0, 0.0)
     scene.collection.objects.link(cam)
     scene.camera = cam
 
diff --git a/examples/driver-wave/preview.webp b/examples/driver-wave/preview.webp
index 81f7a3db..1671d4a6 100644
Binary files a/examples/driver-wave/preview.webp and b/examples/driver-wave/preview.webp differ
diff --git a/examples/gallery.json b/examples/gallery.json
index 3377aa14..080758ad 100644
--- a/examples/gallery.json
+++ b/examples/gallery.json
@@ -73,7 +73,7 @@
       "name": "driver-wave",
       "dir": "examples/driver-wave",
       "teaches": "A driver_namespace function driving sixteen column heights through SCRIPTED drivers — the sine skyline is entirely driver-evaluated.",
-      "alt": "A row of orange bars whose heights rise and fall in a wave, low in the middle and tall at both ends.",
+      "alt": "A row of orange bars seen from above, their heights rising and falling in a wave, low in the middle and tall at both ends, each casting a shadow on the floor.",
       "witnessesFix": "Driven values appear after a view-layer update in two places that must agree: the evaluated copy and the original datablock the animation system flushes for display.",
       "hero": "docs/gallery/assets/driver-wave-hero.webp",
       "preview": "examples/driver-wave/preview.webp",
diff --git a/examples/shader-node-group/README.md b/examples/shader-node-group/README.md
index b26ec9a9..aabff350 100644
--- a/examples/shader-node-group/README.md
+++ b/examples/shader-node-group/README.md
@@ -12,6 +12,14 @@ per-material Tint lives on the group **node**, not inside the group — set it i
 and every material changes at once. The render is the proof: two spheres, one group, two
 colors.
 
+## Staging
+
+The still renders under the Standard view transform on the dark house
+stage; it had no view transform set, so AgX washed both tints toward
+pastel over a lighter floor. The key is larger and softer (the glossy
+spheres had mirrored it as a hard white square), and the camera aims
+at the sphere centres. Render path only.
+
 ## Run
 
 ```bash
diff --git a/examples/shader-node-group/preview.webp b/examples/shader-node-group/preview.webp
index 93a11ef9..76b6bbe3 100644
Binary files a/examples/shader-node-group/preview.webp and b/examples/shader-node-group/preview.webp differ
diff --git a/examples/shader-node-group/shader_node_group.py b/examples/shader-node-group/shader_node_group.py
index d4e1edd7..d4b80894 100644
--- a/examples/shader-node-group/shader_node_group.py
+++ b/examples/shader-node-group/shader_node_group.py
@@ -135,8 +135,8 @@ def render_still(objs, path, engine):
     fmat = bpy.data.materials.new("Studio")
     fmat.use_nodes = True
     fb = fmat.node_tree.nodes["Principled BSDF"]
-    fb.inputs["Base Color"].default_value = (0.055, 0.06, 0.07, 1.0)
-    fb.inputs["Roughness"].default_value = 0.5
+    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)
@@ -147,7 +147,7 @@ def render_still(objs, path, engine):
 
     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
 
     def light(name, loc, energy, size, col, rot):
@@ -158,16 +158,26 @@ def light(name, loc, energy, size, col, rot):
         ob.rotation_euler = tuple(math.radians(a) for a in rot)
         scene.collection.objects.link(ob)
 
-    light("Key", (-4.0, -5.0, 6.5), 1400.0, 5.5, (1.0, 0.98, 0.94), (46, 0, -35))
+    # a large soft key: at 5.5 m the glossy spheres mirrored it as a hard
+    # white square
+    light("Key", (-4.0, -5.0, 6.5), 1100.0, 9.0, (1.0, 0.98, 0.94), (46, 0, -35))
     light("Fill", (5.5, -4.0, 3.0), 280.0, 8.0, (0.82, 0.88, 1.0), (63, 0, 48))
     light("Rim", (0.5, 6.0, 4.0), 900.0, 3.5, (1.0, 0.74, 0.46), (-62, 0, 175))
 
     cam_data = bpy.data.cameras.new("Cam")
-    cam_data.lens = 58.0
+    cam_data.lens = 50.0
     cam = bpy.data.objects.new("Cam", cam_data)
-    cam.location = (0.0, -8.7, 2.6)
-    cam.rotation_euler = (math.radians(78), 0.0, 0.0)
+    cam.location = (0.0, -8.4, 3.3)
     scene.collection.objects.link(cam)
+    # aim at the spheres' centres so they sit mid-frame, not above a band of
+    # empty floor
+    aim = bpy.data.objects.new("Aim", None)
+    aim.location = (0.0, 0.0, 1.0)
+    scene.collection.objects.link(aim)
+    track = cam.constraints.new('TRACK_TO')
+    track.target = aim
+    track.track_axis = 'TRACK_NEGATIVE_Z'
+    track.up_axis = 'UP_Y'
     scene.camera = cam
 
     scene.render.engine = 'CYCLES' if engine == 'cycles' else eevee_engine_id()
@@ -182,6 +192,8 @@ def light(name, loc, energy, size, col, rot):
     scene.render.resolution_y = 720
     scene.render.image_settings.file_format = 'PNG'
     scene.render.filepath = path
+    # AgX would wash both tints toward pastel (docs/VISUAL-STYLE.md)
+    scene.view_settings.view_transform = 'Standard'
     # Layer 1 framing gate (silhouette matte) — exit 10 on violation, before
     # the beauty render so a defective composition ships no artifact.
     fcode = gallery_framing.check_framing(
diff --git a/showcase/README.md b/showcase/README.md
index b3961374..4c1839f9 100644
--- a/showcase/README.md
+++ b/showcase/README.md
@@ -457,6 +457,18 @@ entry in `showcase/gallery.json`, and a rendered still.
   geometry in a different face order from run to run, which the
   `mat_index_counts` print exposed on `wooden-ladder`. Call
   `bm.edges.index_update()` and sort by index first.
+- **A band wraps its host; it is never sunk into it (exit 18).**
+  `hitching-post`'s bands were sized from the post's inner offset, so they
+  sat inside the post and only the chamfered corners broke the surface,
+  as black slits. Size a band from the host's face: inner face a named
+  bite inside it, outer face proud of it. Assert the band's outer
+  half-width against the host's (`--sunk-bands`). An overlap test alone
+  passes a sunk band, because a sunk band overlaps too.
+- **Iron is not chrome.** Cast and forged iron is near-black or rusted
+  and rough. Metallic 1.0 with roughness under 0.4 reads as polished
+  steel or plastic (`hand-pump` read as chrome).
+- **The stage is bigger than the frame.** A 14 m set lets the back
+  wall's edge into the corner of a three-quarter hero. Use 60 m.
 - **A leaning prop is staged against something.** A ladder raked 12° in
   open air reads as falling. Render-only: put a wall section on the side
   it rakes toward, with its face through the top, and turn the piece so
diff --git a/showcase/gallery.json b/showcase/gallery.json
index 5f4e0dd1..0468e8a3 100644
--- a/showcase/gallery.json
+++ b/showcase/gallery.json
@@ -208,8 +208,8 @@
       "name": "hitching-post",
       "dir": "showcase/hitching-post",
       "teaches": "A procedural hitching post (eaved cap, one rail, cup shoe, rings hung through eyes) through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "alt": "A tall wooden hitching post with a pointed cap, a crossbar and two iron rings.",
-      "witnessesFix": "Recomputed: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring exits 18; --short-post exits 19.",
+      "alt": "A tall wooden hitching post with a pointed cap, a crossbar, two iron bands wrapped around the post and two iron rings.",
+      "witnessesFix": "Recomputed: 1680 tris, two materials with 114 wood and 742 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.500×0.149×1.246 m, zmin 0, hygiene and coplanar pairs 0, post seated at z 0.010, ring centerline error 0, bands 6.5 mm proud of the post, LOD ratios in band, convex collider 80 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert and --twin-sole exit 15; --lift-z exits 16; --clip-ring and --sunk-bands exit 18; --short-post exits 19.",
       "hero": "docs/gallery/assets/hitching-post-hero.webp",
       "preview": "showcase/hitching-post/preview.webp",
       "tags": [
@@ -234,7 +234,7 @@
       "name": "hand-pump",
       "dir": "showcase/hand-pump",
       "teaches": "A procedural village hand pump whose gooseneck is a 6-gon tube from the lower-column radius, through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "alt": "A dark iron village hand pump with a curved spout and lever handle on a square wooden plinth.",
+      "alt": "A matte black cast-iron village hand pump with a curved spout and lever handle on a stepped wooden plinth.",
       "witnessesFix": "Recomputed: 1064 tris, two materials with 564 metal and 144 wood faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.610×0.382×1.052 m, grounded zmin, spout-to-column gap 2.7 mm, flange-to-plinth gap 6.0 mm, column radius 62 mm, LOD ratios in band, convex collider 114 tris, hygiene all zero, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z 16; --float-spout 17; --float-flange 18; --skinny-col 19.",
       "hero": "docs/gallery/assets/hand-pump-hero.webp",
       "preview": "showcase/hand-pump/preview.webp",
diff --git a/showcase/hand-pump/README.md b/showcase/hand-pump/README.md
index 053fcb20..8bd3f9c6 100644
--- a/showcase/hand-pump/README.md
+++ b/showcase/hand-pump/README.md
@@ -49,9 +49,23 @@ longer beveled with the plinth. Outer AABB is 0.610 × 0.382 × 1.052 m
 DECIMATE COLLAPSE triangle counts are **not** identical across series —
 5.2.1 is slightly leaner on LOD2. 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. Construction uses no RNG.
-Export byte counts differ by 8 B on 5.2.1 (glTF serializer), not a
-gated axis.
+operator `FINISHED`, not byte-identity. Construction is closed-form;
+the only RNG is the seeded per-piece wood tone. Bevel inputs are sorted by edge index, so the face order is the same on
+every run; a Python set of edges handed to the bevel had made it vary.
+Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis.
+
+### Surface and stage
+
+The quality pass found no geometric defect: every joint checked in the
+inspection sheet (spout root, flange bolts, head and handle pivot,
+column step, plinth) seats as the joint budgets say. The defects were
+on the surface. The iron was polished metal (metallic 1.0, roughness
+0.38) and read as chrome; it is now near-black painted cast iron with
+dark rust in the pores. The plinth slabs and the handle grip carry their
+own wood tone and grain. The stage grid grew from 14 to 60 m, because
+the wall's left edge showed in the corner of the hero. The temp `.glb`
+is removed after its size is measured. With no new geometric defect,
+there is no new budget.
 
 ### Hygiene
 
diff --git a/showcase/hand-pump/hand_pump.py b/showcase/hand-pump/hand_pump.py
index 2c5639fb..22ec2626 100644
--- a/showcase/hand-pump/hand_pump.py
+++ b/showcase/hand-pump/hand_pump.py
@@ -15,7 +15,8 @@
 ``--stray-vert``, ``--lift-z``, ``--float-spout``, ``--float-flange``,
 ``--skinny-col``.
 
-No RNG. Construction is closed-form. DECIMATE COLLAPSE triangle counts
+Construction is closed-form; the only RNG is the seeded per-piece wood
+tone. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
 ratio band, not an exact count.
 
@@ -26,6 +27,7 @@
 import argparse
 import math
 import os
+import random
 import sys
 import tempfile
 import traceback
@@ -87,6 +89,11 @@
 WOOD_IDX = 0
 METAL_IDX = 1
 
+# 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
+
 DOUBLES_EPS = 1e-5
 AREA_EPS = 1e-10
 ZMIN_EPS = 1e-4
@@ -397,6 +404,10 @@ def build_hand_pump_mesh(
         )
         if bevel_offset > 0.0:
             edges = list({e for v in wood for e in v.link_edges})
+            # set order follows memory addresses; sort so the bevel, and the
+            # face order it produces, are the same on every run
+            bm.edges.index_update()
+            edges.sort(key=lambda e: e.index)
             ret = bmesh.ops.bevel(
                 bm,
                 geom=edges,
@@ -572,6 +583,132 @@ def principled(name, color, metallic, roughness, noise_scale=0.0, wear=None):
     return mat
 
 
+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.
+
+    Each plinth slab and the handle grip is its own shell, so each gets
+    one tone and grain running along its own long axis.
+    """
+    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 slab and the grip (``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 pump_materials():
+    """(wood, iron): shared by the check, the render and inspection.
+
+    A cast-iron pump is painted near-black and weathers to rust at the
+    edges and pores; the first build was polished metal (metallic 1.0,
+    roughness 0.38) and read as chrome.
+    """
+    wood = wood_material("HandPumpWood")
+    metal = principled(
+        "HandPumpIron", (0.045, 0.047, 0.050, 1.0), 0.55, 0.52,
+        noise_scale=24.0, wear=(0.09, 0.05, 0.03, 1.0),
+    )
+    return wood, metal
+
+
 def assign_slots(obj, wood, metal):
     mats = obj.data.materials
     wanted = (wood, metal)
@@ -902,14 +1039,9 @@ def check(
     )
     low = build_hand_pump_mesh("HandPumpLow", bevel_offset=0.004, bevel_segments=2, **kw)
     high = build_hand_pump_mesh("HandPumpHigh", bevel_offset=0.004, bevel_segments=4, **kw)
-    wood = principled(
-        "HandPumpWood", (0.36, 0.19, 0.07, 1.0), 0.0, 0.60,
-        noise_scale=14.0, wear=(0.22, 0.12, 0.05, 1.0),
-    )
-    metal = principled(
-        "HandPumpIron", (0.18, 0.175, 0.17, 1.0), 1.0, 0.38,
-        noise_scale=18.0, wear=(0.28, 0.24, 0.18, 1.0),
-    )
+    wood, metal = pump_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
 
@@ -965,6 +1097,10 @@ 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)
 
     hyg = hygiene_audit(low.data)
     zf = zfight_pairs(low.data)
@@ -1120,7 +1256,9 @@ def render_still(low, wood, tex, path, engine):
     floor_me = bpy.data.meshes.new("Floor")
     bm = bmesh.new()
     try:
-        bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=14.0)
+        # Oversized so no edge of the set can enter frame; at 14 m the wall's
+        # left edge showed as a bright band in the corner of the hero.
+        bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=60.0)
         bm.to_mesh(floor_me)
     finally:
         bm.free()
diff --git a/showcase/hand-pump/preview.webp b/showcase/hand-pump/preview.webp
index 433b95b0..3daf2d8e 100644
Binary files a/showcase/hand-pump/preview.webp and b/showcase/hand-pump/preview.webp differ
diff --git a/showcase/hitching-post/README.md b/showcase/hitching-post/README.md
index d7354fcc..a00e6b47 100644
--- a/showcase/hitching-post/README.md
+++ b/showcase/hitching-post/README.md
@@ -38,9 +38,10 @@ materials, UVs, evaluated LOD, collider, or export file.
 | Post seat | world zmin in (0.004, 0.014), XY centroid within 0.010 of origin, arm axis cos ≥ cos(0.5°) | 0.01000, 0, 1.000 |
 | Hung ring | centerline error ≤ 0.008 m, ring–wood overlap 0, eye–wood overlap 0, shank–ring overlap 0, shank bites the eye | 0, 0, 0, 0, 40 |
 | Shoe | each band overlaps the post, shoe overlaps the sole | band gap 0, sole–shoe 8 |
+| **Band seat** | each band above the shoe stands ≥ 0.004 m proud of the post faces | 0.00650 |
 | Wood–metal gap | BVH surface < 0.008 m | 0.00075 |
 | Collider tris | ≤ 280 | 80 |
-| Export | written, size > 0 | 127428 / 127428 / 127412 bytes |
+| Export | written, size > 0 | 127424 / 127424 / 127412 bytes |
 
 Base triangles rose from **1598 to 1680**. The old rings were faceted
 tori clipped into the arm; the new eyes, shanks, and 24-segment hung
@@ -50,9 +51,25 @@ budget stays at 0.
 DECIMATE COLLAPSE triangle counts are **not** identical across series —
 the gate is a ratio band, not an exact count. On this mesh the three
 binaries agreed. Bake pixels are stochastic; the gate is `has_data`
-plus operator `FINISHED`, not byte-identity. Construction uses no RNG.
-Export byte counts differ by 16 B on 5.2.1 (glTF serializer), not a
-gated axis. Euler is 12 (six balls and seven tori) and is not gated to 2.
+plus operator `FINISHED`, not byte-identity. Construction is
+closed-form; the only RNG is the seeded per-piece wood tone. Bevel inputs are sorted by edge index, so the face order is the same on
+every run; a Python set of edges handed to the bevel had made it vary.
+Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis. Euler is 12 (six balls and seven tori) and is not gated to 2.
+
+### Bands, wood and stage
+
+The two iron bands were sized from `half - grip`: an inner half-width of
+53 mm and an outer one of 61 mm, against a 62.5 mm post face. They sat
+inside the post, and only the chamfered corners broke the surface,
+showing as small black slits up the post. They now wrap it: the inner
+face bites 1.5 mm into the post (`BAND_BITE`), so each band stands
+6.5 mm proud. **Band seat** asserts it; `--sunk-bands` restores the old
+bands and exits 18 (proud −0.0015 m).
+
+The post, rail and cap each carry their own tone and grain, and the
+iron is rusted. The stage grid grew from 14 to 60 m, because the wall's
+left edge showed as a bright band in the corner of the hero. The temp
+`.glb` is removed after its size is measured.
 
 Each falsifier violates exactly one named budget. Proven on Blender
 4.5.11 LTS, 5.1.2, and 5.2.1 LTS (the binaries' own `--version`):
@@ -65,6 +82,7 @@ Each falsifier violates exactly one named budget. Proven on Blender
 | `--lift-z` | Grounded zmin | 16 | zmin 0.050000 |
 | `--clip-ring` | Hung-ring centerline | 18 | ring_err 0.024, ring–wood overlap 32 |
 | `--short-post` | Seated post | 19 | post zmin 0.030 |
+| `--sunk-bands` | Band seat | 18 | band proud −0.0015 |
 
 Default exit is 0 on all three. `--clip-ring` also overlaps the rail;
 the centerline gate is the one that fires.
@@ -79,6 +97,7 @@ blender --background --python hitching_post.py -- --twin-sole
 blender --background --python hitching_post.py -- --lift-z
 blender --background --python hitching_post.py -- --clip-ring
 blender --background --python hitching_post.py -- --short-post
+blender --background --python hitching_post.py -- --sunk-bands
 blender --background --python hitching_post.py -- --output preview.webp --engine cycles
 ```
 
@@ -109,5 +128,5 @@ File-local. `9` is a valid check code. `10` is reserved for
 | 15 | Hygiene, including coplanar pairs (`--stray-vert`, `--twin-sole`) |
 | 16 | Grounded zmin (`--lift-z`) |
 | 17 | Wood–metal BVH gap above 8 mm |
-| 18 | Hung ring or shoe seat (`--clip-ring`) |
+| 18 | Hung ring, shoe or band seat (`--clip-ring`, `--sunk-bands`) |
 | 19 | Post plumb, origin, and cup seat (`--short-post`) |
diff --git a/showcase/hitching-post/hitching_post.py b/showcase/hitching-post/hitching_post.py
index 95e663c8..07c48145 100644
--- a/showcase/hitching-post/hitching_post.py
+++ b/showcase/hitching-post/hitching_post.py
@@ -13,9 +13,12 @@
 vertex so the hygiene budget fails. ``--twin-sole`` duplicates the shoe
 plate so the coplanar-face budget fails. ``--clip-ring`` lifts a hung
 ring off the eye centerline. ``--short-post`` starts the post above the
-shoe cup so the seated-post budget fails.
+shoe cup so the seated-post budget fails. ``--sunk-bands`` builds the
+iron bands inside the post, as the piece first shipped, so the band-seat
+budget fails.
 
-No RNG. Construction is closed-form. DECIMATE COLLAPSE triangle counts
+Construction is closed-form; the only RNG is the seeded per-piece wood
+tone. DECIMATE COLLAPSE triangle counts
 are not byte-identical across Blender versions — the LOD gate is a
 ratio band, not an exact count.
 
@@ -26,11 +29,13 @@
     blender --background --python hitching_post.py -- --twin-sole
     blender --background --python hitching_post.py -- --clip-ring
     blender --background --python hitching_post.py -- --short-post
+    blender --background --python hitching_post.py -- --sunk-bands
     blender --background --python hitching_post.py -- --output hitching-post.png
 """
 import argparse
 import math
 import os
+import random
 import sys
 import tempfile
 import traceback
@@ -68,6 +73,16 @@
 BAND_H = 0.026
 BAND_T = 0.008
 BAND_ZS = (0.24, 0.56)
+# Bands wrap the post: inner face BAND_BITE inside the post face, so each
+# band stands BAND_T - BAND_BITE proud. The first build sized them from
+# ``half - grip`` and sank them inside the post, so only the chamfered
+# corners broke the surface, as black slits. --sunk-bands restores that.
+BAND_BITE = 0.0015
+BAND_PROUD_MIN = 0.004
+# 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
 # Ring tube must fit through the eye: RING_MINOR < EYE_MAJOR - EYE_MINOR.
 RING_FIT = 0.004
 POST_ZMIN_LO = 0.004
@@ -469,6 +484,7 @@ def seat_audit(me):
         "shanks": 0,
         "shank_ring": 99,
         "shank_eye": 0,
+        "band_proud": -1.0,
     }
     if (
         post is None
@@ -517,6 +533,17 @@ def seat_audit(me):
     shoe = min(bands, key=lambda b: b["z0"])
     sole_shoe = len(_bvh(me, soles[0]["polys"]).overlap(_bvh(me, shoe["polys"])))
 
+    # Each band above the shoe must stand proud of the post faces: its
+    # outer half-width in plan against the post's.
+    post_x0, post_x1, post_y0, post_y1, _pz0, _pz1 = _bounds(me, post["idxs"])
+    post_half = 0.25 * ((post_x1 - post_x0) + (post_y1 - post_y0))
+    band_proud = 99.0
+    for band in bands:
+        if band is shoe:
+            continue
+        bx0, bx1, by0, by1, _bz0, _bz1 = _bounds(me, band["idxs"])
+        band_proud = min(band_proud, 0.25 * ((bx1 - bx0) + (by1 - by0)) - post_half)
+
     pos, neg = [], []
     for i in arm["idxs"]:
         co = me.vertices[i].co
@@ -543,6 +570,7 @@ def seat_audit(me):
         "shanks": len(shanks),
         "shank_ring": shank_ring,
         "shank_eye": shank_eye,
+        "band_proud": band_proud,
     })
     return out
 
@@ -674,6 +702,7 @@ def build_hitching_post_mesh(
     clip_ring=False,
     twin_sole=False,
     small_cap=False,
+    sunk_bands=False,
 ):
     """Post on a closed shoe, one rail, rings hung through eyes under the rail.
 
@@ -704,6 +733,10 @@ def build_hitching_post_mesh(
         )
         if bevel_offset > 0.0:
             edges = list({e for v in wood for e in v.link_edges if v.is_valid})
+            # set order follows memory addresses; sort so the bevel, and the
+            # face order it produces, are the same on every run
+            bm.edges.index_update()
+            edges.sort(key=lambda e: e.index)
             ret = bmesh.ops.bevel(
                 bm,
                 geom=edges,
@@ -753,8 +786,9 @@ def build_hitching_post_mesh(
             wall_z1 - wall_z0,
             METAL_IDX,
         )
+        band_in = (half - grip) if sunk_bands else (half - BAND_BITE)
         for z in BAND_ZS:
-            add_square_band(bm, z, half - grip, BAND_T, BAND_H, METAL_IDX)
+            add_square_band(bm, z, band_in, BAND_T, BAND_H, METAL_IDX)
 
         arm_bottom = ARM_Z - ARM_ZTH * 0.5
         eye_z = arm_bottom - EYE_MAJOR - EYE_MINOR - 0.004
@@ -843,6 +877,127 @@ def principled(name, color, metallic, roughness, noise_scale=0.0, wear=None):
     return mat
 
 
+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.
+
+    The post, the rail and the cap are each their own shell, so each gets
+    one tone and grain running along its own long axis.
+    """
+    tone = [0.5] * len(me.polygons)
+    grain = [(0.0, 0.0, 1.0)] * len(me.polygons)
+    owner = {}
+    rng = random.Random(TONE_SEED)
+    for g, _polys in _face_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 the post and rail (``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 post_materials():
+    """(wood, iron): shared by the check, the render and inspection."""
+    wood = wood_material("HitchPostWood")
+    metal = principled(
+        "HitchPostIron", (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 assign_slots(obj, wood, metal):
     mats = obj.data.materials
     wanted = (wood, metal)
@@ -979,6 +1134,7 @@ def check(
     twin_sole=False,
     clip_ring=False,
     short_post=False,
+    sunk_bands=False,
 ):
     bpy.ops.wm.read_factory_settings(use_empty=True)
     low = build_hitching_post_mesh(
@@ -988,24 +1144,14 @@ def check(
         short_post=short_post,
         clip_ring=clip_ring,
         twin_sole=twin_sole,
+        sunk_bands=sunk_bands,
     )
-    high = build_hitching_post_mesh("HitchPostHigh", bevel_offset=0.008, bevel_segments=4)
-    wood = principled(
-        "HitchPostWood",
-        (0.36, 0.19, 0.07, 1.0),
-        0.0,
-        0.62,
-        noise_scale=11.0,
-        wear=(0.24, 0.13, 0.05, 1.0),
-    )
-    metal = principled(
-        "HitchPostIron",
-        (0.16, 0.155, 0.15, 1.0),
-        1.0,
-        0.48,
-        noise_scale=16.0,
-        wear=(0.09, 0.085, 0.08, 1.0),
+    high = build_hitching_post_mesh(
+        "HitchPostHigh", bevel_offset=0.008, bevel_segments=4, sunk_bands=sunk_bands,
     )
+    wood, metal = post_materials()
+    paint_planks(low.data)
+    paint_planks(high.data)
     assign_slots(low, wood, metal)
     assign_slots(high, wood, metal)
     if lift_z:
@@ -1060,6 +1206,10 @@ 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(
@@ -1096,7 +1246,8 @@ def check(
         f"band_gap={seat['band_gap']:.5f} sole_shoe={seat['sole_shoe']} "
         f"shank_ring={seat['shank_ring']} shank_eye={seat['shank_eye']} "
         f"parts={seat['post']}/{seat['arm']}/{seat['cap']}/"
-        f"soles={seat['soles']}/rings={seat['rings']}/eyes={seat['eyes']}/bands={seat['bands']}"
+        f"soles={seat['soles']}/rings={seat['rings']}/eyes={seat['eyes']}/bands={seat['bands']} "
+        f"band_proud={seat['band_proud']:.5f}"
     )
 
     if not (BASE_TRIS_MIN <= base_tris <= BASE_TRIS_MAX):
@@ -1202,13 +1353,15 @@ def check(
         or seat["sole_shoe"] < 1
         or seat["shank_ring"]
         or seat["shank_eye"] < 1
+        or seat["band_proud"] < BAND_PROUD_MIN
     ):
         return fail(
             f"hung ring / shoe seat ring_err={seat['ring_err']:.5f} "
             f"ring_wood={seat['ring_wood']} eye_wood={seat['eye_wood']} "
             f"band_gap={seat['band_gap']:.5f} sole_shoe={seat['sole_shoe']} "
             f"shank_ring={seat['shank_ring']} shank_eye={seat['shank_eye']} "
-            "(--clip-ring is the designed fail)",
+            f"band_proud={seat['band_proud']:.5f} (min {BAND_PROUD_MIN}) "
+            "(--clip-ring / --sunk-bands are the designed fails)",
             18,
         ), None, None, None, None, None
     if (
@@ -1248,7 +1401,9 @@ def render_still(low, wood, tex, path, engine):
     floor_me = bpy.data.meshes.new("Floor")
     bm = bmesh.new()
     try:
-        bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=14.0)
+        # Oversized so no edge of the set can enter frame; at 14 m the wall's
+        # left edge showed as a bright band in the corner of the hero.
+        bmesh.ops.create_grid(bm, x_segments=1, y_segments=1, size=60.0)
         bm.to_mesh(floor_me)
     finally:
         bm.free()
@@ -1365,6 +1520,11 @@ def main():
         action="store_true",
         help="falsification: start the post above the shoe cup",
     )
+    p.add_argument(
+        "--sunk-bands",
+        action="store_true",
+        help="falsification: bands inside the post, only the corners showing",
+    )
     args = p.parse_args(argv)
 
     code, low, _high, wood, tex, _col = check(
@@ -1374,6 +1534,7 @@ def main():
         twin_sole=args.twin_sole,
         clip_ring=args.clip_ring,
         short_post=args.short_post,
+        sunk_bands=args.sunk_bands,
     )
     if code:
         return code
diff --git a/showcase/hitching-post/preview.webp b/showcase/hitching-post/preview.webp
index 2c93144a..5feac66a 100644
Binary files a/showcase/hitching-post/preview.webp and b/showcase/hitching-post/preview.webp differ