fix: shipping-crate, shape-key-blend and vse-linear-modifiers quality pass (#231)

* fix(showcase): shipping-crate quality pass — one-shell nailed straps, handles on a board

Each strap was two unbevelled boxes flush on the post; it is now one
chamfered L-section biting into the post, nailed (seat budget, exit 18,
--float-nails). Handle mounting plates straddled an end-board gap; the
handle now snaps to the nearest board's centre and a budget asserts each
plate sits inside one board (exit 20, --straddle-handle). Per-plank tone
and grain. The temp glTF export is removed after measuring.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

* fix(examples): shape-key-blend still cages the checked block with its key endpoints

Render path only. The check, its assertions and exit codes are unchanged.
docs/gallery/index.html also carries the shipping-crate card alt.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

* docs(examples): vse-linear-modifiers names Strip, not the nonexistent Sequence type

Docstring and README only; assertions and exit codes unchanged.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

* docs(showcase): convention for fixtures mounted on one board

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

---------

Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: TMHSDigital

docs/gallery/assets/shape-key-blend-hero.webp

@@ -464,7 +464,7 @@ <h2><a href="gn-modifier-inputs/">gn-modifier-inputs</a></h2>
       </article>
       <article class="card" data-tags="mesh shape-keys">
         <a class="card-media" href="shape-key-blend/" tabindex="-1" aria-hidden="true">
-          <img src="assets/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare." loading="lazy" decoding="async" />
+          <img src="assets/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="shape-key-blend/">shape-key-blend</a></h2>
@@ -904,7 +904,7 @@ <h2><a href="gn-socket-rename/">gn-socket-rename</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="shipping-crate/" tabindex="-1" aria-hidden="true">
-          <img src="assets/shipping-crate-hero.webp" alt="A wooden shipping crate with dark corner posts, horizontal planks and a metal handle." loading="lazy" decoding="async" />
+          <img src="assets/shipping-crate-hero.webp" alt="A grained wooden shipping crate with nailed iron corner straps, horizontal planks and a metal bail handle mounted on one end board." loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="shipping-crate/">shipping-crate</a></h2>

docs/gallery/assets/shipping-crate-hero.webp

@@ -16,13 +16,13 @@
   <meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/shape-key-blend-hero.webp" />
   <meta property="og:image:width" content="1280" />
   <meta property="og:image:height" content="720" />
-  <meta property="og:image:alt" content="Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare." />
+  <meta property="og:image:alt" content="Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it." />
   <meta property="og:site_name" content="Blender Developer Tools" />
   <meta name="twitter:card" content="summary_large_image" />
   <meta name="twitter:title" content="shape-key-blend — Examples — Blender Developer Tools" />
   <meta name="twitter:description" content="A relative Tall shape key that lifts and flares the top face — authored via shape_key_add / key_blocks / .value — read back from the depsgraph-evaluated mesh." />
   <meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/shape-key-blend-hero.webp" />
-  <meta name="twitter:image:alt" content="Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare." />
+  <meta name="twitter:image:alt" content="Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it." />
   <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>shape-key-blend</h1>
     <p>A relative Tall shape key that lifts and flares the top face — authored via shape_key_add / key_blocks / .value — read back from the depsgraph-evaluated mesh.</p>
   </header>
   <main id="main">
-    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare.">
-      <img src="../assets/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare." width="1280" height="720" />
+    <button class="detail-hero" id="heroZoom" type="button" aria-label="View full size: Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it.">
+      <img src="../assets/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it." 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> Shape keys do not rewrite mesh.vertices: every evaluated vert matches basis + value × (key − basis), including the flared top half-extent.</div>
@@ -460,6 +460,30 @@ <h2>Source</h2>
         ob.rotation_euler = (<span class="n">0.0</span>, <span class="n">0.0</span>, math.radians(<span class="n">28</span>))
         blocks.append(ob)
 
+    <span class="c"># Endpoint cages on the checked block: its Basis and its full Tall key as</span>
+    <span class="c"># pale wireframes, so the solid visibly sits halfway between the two —</span>
+    <span class="c"># the closed-form blend the check asserts, not just &quot;a taller box&quot;.</span>
+    <span class="c"># Render-only copies with their own key value; `obj` is untouched.</span>
+    cage_mat = bpy.data.materials.new(<span class="s">&quot;Cage&quot;</span>)
+    cage_mat.use_nodes = <span class="k">True</span>
+    cbsdf = cage_mat.node_tree.nodes[<span class="s">&quot;Principled BSDF&quot;</span>]
+    cbsdf.inputs[<span class="s">&quot;Base Color&quot;</span>].default_value = (<span class="n">0.92</span>, <span class="n">0.84</span>, <span class="n">1.0</span>, <span class="n">1.0</span>)
+    cbsdf.inputs[<span class="s">&quot;Roughness&quot;</span>].default_value = <span class="n">0.4</span>
+    cages = []
+    <span class="k">for</span> end <span class="k">in</span> (<span class="n">0.0</span>, <span class="n">1.0</span>):
+        me = obj.data.copy()
+        me.materials.clear()
+        me.materials.append(cage_mat)
+        me.shape_keys.key_blocks[<span class="s">&quot;Tall&quot;</span>].value = end
+        cage = bpy.data.objects.new(<span class="s">f&quot;</span><span class="s">Cage_</span>{end}<span class="s">&quot;</span>, me)
+        cage.location = obj.location
+        cage.rotation_euler = obj.rotation_euler
+        wire = cage.modifiers.new(<span class="s">&quot;cage&quot;</span>, <span class="s">&quot;WIREFRAME&quot;</span>)
+        wire.thickness = <span class="n">0.02</span>
+        wire.use_even_offset = <span class="k">True</span>
+        bpy.context.collection.objects.link(cage)
+        cages.append(cage)
+
     floor_me = bpy.data.meshes.new(<span class="s">&quot;Floor&quot;</span>)
     bm = bmesh.new()
     <span class="k">try</span>:
@@ -487,7 +511,9 @@ <h2>Source</h2>
 
     world_top = HALF + EXPECT_TOP_Z
     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>, world_top / <span class="n">2</span>)
+    <span class="c"># Aimed above the checked block&#x27;s middle: the full-key cage over it is</span>
+    <span class="c"># taller than any solid, and centring on the solids clipped it.</span>
+    aim.location = (<span class="n">0.35</span>, <span class="n">0.0</span>, world_top * <span class="n">0.62</span>)
     scene.collection.objects.link(aim)
 
     <span class="k">def</span> light(name, loc, energy, size, col):
@@ -520,7 +546,8 @@ <h2>Source</h2>
     cam_data = bpy.data.cameras.new(<span class="s">&quot;Cam&quot;</span>)
     cam_data.lens = <span class="n">50.0</span>
     cam = bpy.data.objects.new(<span class="s">&quot;Cam&quot;</span>, cam_data)
-    cam.location = (<span class="n">0.0</span>, -<span class="n">8.8</span>, <span class="n">2.05</span>)
+    <span class="c"># Pulled back so the full-key cage on the right block stays in frame.</span>
+    cam.location = (<span class="n">0.35</span>, -<span class="n">10.4</span>, <span class="n">2.5</span>)
     scene.collection.objects.link(cam)
     scene.camera = cam
     track = cam.constraints.new(<span class="s">&#x27;TRACK_TO&#x27;</span>)
@@ -581,7 +608,7 @@ <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/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts, from a plain cube to a strong flare." />
+    <img src="../assets/shape-key-blend-hero.webp" alt="Three purple boxes flaring wider at the top by increasing amounts; the rightmost sits inside a pale wire cage of its full shape key, halfway to it." />
   </dialog>
   <footer>
     <div class="statusbar">