fix(showcase): iron-cauldron and shipping-crate visual quality pass (#176)

* fix(showcase): lock iron-cauldron coaxial ferrules as hygiene budgets

World-Z cups let leaning poles slice the lip. Coaxial shoes plus pole-axis bite keep the joint closed without a magic offset.

Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(showcase): lock shipping-crate tenons and filleted handles as hygiene budgets

Posts hung over a skid cave and 90-degree handle lofts sat on the plates. Shared post/skid planes and quarter-circle bails close those joints without magic offsets.

Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: TMHSDigital

docs/gallery/assets/iron-cauldron-hero.webp

@@ -892,7 +892,7 @@ <h2><a href="gn-socket-rename/">gn-socket-rename</a></h2>
         <div class="card-body">
           <h2><a href="shipping-crate/">shipping-crate</a></h2>
           <p class="teaches">A procedural shipping crate 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: 624 tris, two materials with 132 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.352×0.856×0.748 m, LOD ratios in band (5.2 COLLAPSE more aggressive), convex collider 36 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 2508 tris, two materials with 1170 wood and 280 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.146×0.726×0.612 m, grounded zmin, 3 skids, handle-end and slat-post join 0, mesh hygiene all zero, LOD ratios in band (5.2 COLLAPSE leaner on LOD2), convex collider 76 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z/--short-skids 16; --float-handle 17; --omit-slats 18.</p>
           <a class="card-link" href="shipping-crate/">View example <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
@@ -1145,7 +1145,7 @@ <h2><a href="tavern-stool/">tavern-stool</a></h2>
         <div class="card-body">
           <h2><a href="iron-cauldron/">iron-cauldron</a></h2>
           <p class="teaches">A procedural hanging iron cauldron with a bulged open pot, bail, and timber tripod 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: 3388 tris, two materials with 450 wood and 1198 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.013×0.986×0.827 m, pot–leg clearance 0.051 m, LOD ratios in band (5.2 COLLAPSE 8 tris leaner on LOD2), convex collider 98 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 3664 tris, two materials with 224 wood and 1768 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.987×0.961×0.860 m, pot–leg clearance 0.046 m, 3 coaxial ferrules at zmin 0, ferrule bite −0.00185 m, hook-bail join 0, mesh hygiene all zero, LOD ratios in band, convex collider 250 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z/--short-legs 16; --float-hook 17; --pipe-ferrule 18.</p>
           <a class="card-link" href="iron-cauldron/">View example <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>

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

@@ -9,7 +9,7 @@
       "name": "shipping-crate",
       "dir": "showcase/shipping-crate",
       "teaches": "A procedural shipping crate through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "witnessesFix": "Recomputed: 624 tris, two materials with 132 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.352×0.856×0.748 m, LOD ratios in band (5.2 COLLAPSE more aggressive), convex collider 36 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.",
+      "witnessesFix": "Recomputed: 2508 tris, two materials with 1170 wood and 280 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.146×0.726×0.612 m, grounded zmin, 3 skids, handle-end and slat-post join 0, mesh hygiene all zero, LOD ratios in band (5.2 COLLAPSE leaner on LOD2), convex collider 76 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z/--short-skids 16; --float-handle 17; --omit-slats 18.",
       "hero": "docs/gallery/assets/shipping-crate-hero.webp",
       "preview": "showcase/shipping-crate/preview.webp",
       "tags": [
@@ -285,7 +285,7 @@
       "name": "iron-cauldron",
       "dir": "showcase/iron-cauldron",
       "teaches": "A procedural hanging iron cauldron with a bulged open pot, bail, and timber tripod through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "witnessesFix": "Recomputed: 3388 tris, two materials with 450 wood and 1198 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.013×0.986×0.827 m, pot–leg clearance 0.051 m, LOD ratios in band (5.2 COLLAPSE 8 tris leaner on LOD2), convex collider 98 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.",
+      "witnessesFix": "Recomputed: 3664 tris, two materials with 224 wood and 1768 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.987×0.961×0.860 m, pot–leg clearance 0.046 m, 3 coaxial ferrules at zmin 0, ferrule bite −0.00185 m, hook-bail join 0, mesh hygiene all zero, LOD ratios in band, convex collider 250 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z/--short-legs 16; --float-hook 17; --pipe-ferrule 18.",
       "hero": "docs/gallery/assets/iron-cauldron-hero.webp",
       "preview": "showcase/iron-cauldron/preview.webp",
       "tags": [

docs/gallery/index.html

@@ -1,9 +1,16 @@
 # Iron cauldron
 
-A showcase piece, not an example. Procedural hanging cauldron (bulged
-iron pot with an open mouth, bail, timber tripod) then the shipped
-pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain,
-convex collider, Unity glTF export.
+A showcase piece, not an example. Procedural hanging cauldron (lathed
+iron pot with a rolled rim, pipe bail through vertical ear rings, timber
+tripod tenoned into a turned crown, iron ferrule cups coaxial with the
+poles) then the shipped pipeline: unique-cell UVs, Cycles high-to-low
+normal bake, LOD chain, convex collider, Unity glTF export.
+
+Ferrules are lofted along the pole axis and shifted so the downhill rim
+sits at Z=0. A world-Z bucket lets a leaning pole slice the lip.
+`ferrule_bite` is measured in that same frame, and only samples wood
+inside the cup's own axis span — a pole hovering above the well cannot
+fake a seat.
 
 It asserts **budget conformance** of the generated result. It does not
 witness an API contract. "It rendered without error" is not a check.
@@ -21,41 +28,83 @@ materials, UVs, evaluated LOD, collider, or export file.
 
 | Axis | Declared | Measured (4.5.11 / 5.1.2 / 5.2.1) |
 | --- | --- | --- |
-| Base triangles | 3280–3520 | 3388 / 3388 / 3388 |
+| Base triangles | 2800–4200 | 3664 / 3664 / 3664 |
 | LOD1 ratio | 0.32–0.62 of base | 0.5000 / 0.5000 / 0.5000 |
-| LOD2 ratio | 0.10–0.35 of base | 0.2196 / 0.2196 / 0.2172 |
-| Materials | exactly 2 distinct, ≥12 wood, ≥24 metal | 2 slots, 450 wood, 1198 metal |
+| LOD2 ratio | 0.10–0.35 of base | 0.2200 / 0.2200 / 0.2200 |
+| Materials | exactly 2 distinct; ≥80 wood, ≥200 metal faces | 2 slots; 224 / 1768 |
 | UVs | in `0..1`, AABB overlap ≤ 1e-5 | in range, overlap 0 |
-| Outer AABB | (1.013, 0.986, 0.827) m ± 0.01 | (1.0128, 0.9865, 0.8271), zmin 0.002 |
-| Pot–leg clearance | ≥ 0.04 m (recomputed vs pole axes) | 0.0513 / 0.0513 / 0.0513 |
-| Collider tris | ≤ 200 | 98 |
-| Export | written, size > 0 | 245060 / 245060 / 245044 bytes |
+| Outer AABB | (0.987, 0.961, 0.860) m ± 0.015 | (0.9866, 0.9605, 0.8600), zmin 0 |
+| Collider tris | ≤ 280 | 250 |
+| Export | written, size > 0 | 287916 / 287916 / 287904 bytes |
+
+Base triangles rose from **3388 to 3664** in the quality pass: coaxial
+ferrule cups and a dual-wall lathe with a rolled rim replaced the old
+cone-tripod / overlapping-torus construction.
+
+### Hygiene
+
+Recomputed from the generated mesh, not asserted about the script.
+
+| Axis | Declared | Measured (all three) |
+| --- | --- | --- |
+| Non-manifold edges | 0 | 0 |
+| Loose verts / edges | 0 / 0 | 0 / 0 |
+| Doubles merged at 1e-5 | 0 | 0 |
+| Zero-area faces | 0 | 0 |
+| N-gons | 0 | 0 |
+| Coplanar disjoint face pairs | 0 | 0 |
+| Grounded: `zmin` | within 1e-4 of 0 | 0.0000 |
+| Named supports: 3 ferrules | each `zmin` ≤ 1e-3 | 3, cup_z 0.00000 |
+| Pot size | 0.355 m dia × 0.334 m high ± 0.04 | 0.3545 × 0.3340 |
+| Pot–leg clearance | ≥ 0.04 m | 0.0464 |
+
+### Joint fit and seat
+
+| Axis | Declared | Measured (all three) |
+| --- | --- | --- |
+| Hook-bail BVH gap | ≤ 0.010 m | 0.00000 |
+| Ferrule bite (pole r − inner wall, pole frame) | −0.006–0.000 m | −0.00185 |
 
 DECIMATE COLLAPSE triangle counts are **not** identical across series —
-5.2.1 is 8 tris 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 16 B on 5.2.1 (glTF serializer), not a gated axis.
-The pot–leg clearance is recomputed from shell verts vs the three pole
-axes; clipping exits 3.
+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
+12 B on 5.2.1 (glTF serializer), not a gated axis.
 
-`--skip-decimate` skips the LOD DECIMATE stage so LOD1 ratio is 1.0 and
-exit 9 fires. That is the named budget the falsifier violates.
+### Falsifiers
+
+Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and
+5.2.1 and returned the same code on each.
+
+| Flag | Budget violated | Exit |
+| --- | --- | --- |
+| `--skip-decimate` | LOD1 ratio band | 9 |
+| `--stray-vert` | loose vertex count is 0 | 15 |
+| `--lift-z` | bounding box `zmin` is 0 | 16 |
+| `--short-legs` | named ferrule supports at Z=0 | 16 |
+| `--float-hook` | hook-bail gap | 17 |
+| `--pipe-ferrule` | ferrule bite (pole starts above the well) | 18 |
 
 ## Run
 
 ```bash
 blender --background --python iron_cauldron.py --
 blender --background --python iron_cauldron.py -- --skip-decimate
+blender --background --python iron_cauldron.py -- --stray-vert
+blender --background --python iron_cauldron.py -- --lift-z
+blender --background --python iron_cauldron.py -- --short-legs
+blender --background --python iron_cauldron.py -- --float-hook
+blender --background --python iron_cauldron.py -- --pipe-ferrule
 blender --background --python iron_cauldron.py -- --output cauldron.png
 ```
 
-Smoke does not pass `--output` or `--skip-decimate`.
+Smoke passes no flags.
 
 ## Exit codes
 
 File-local. `9` is a valid check code. `10` is reserved for
-`gallery_framing.check_framing` on the `--output` path.
+`gallery_framing.check_framing` on the `--output` path. `15`–`19` are the
+hygiene and joint-fit family.
 
 | Code | Meaning |
 | --- | --- |
@@ -64,7 +113,7 @@ File-local. `9` is a valid check code. `10` is reserved for
 | 2 | argparse / usage |
 | 3 | Mesh did not build / no UV layer / pot clips tripod |
 | 4 | Base triangle count outside range |
-| 5 | Material count ≠ 2 distinct slots, or wood/metal faces missing |
+| 5 | Material count ≠ 2 distinct slots, or a face-count floor missed |
 | 6 | UVs outside 0..1 |
 | 7 | UV AABB overlap above tolerance |
 | 8 | World AABB off declared outer size |
@@ -74,3 +123,8 @@ File-local. `9` is a valid check code. `10` is reserved for
 | 12 | Bake did not finish or image has no data |
 | 13 | Export file missing or empty |
 | 14 | `--output` produced no file |
+| 15 | Mesh hygiene: loose, non-manifold, zero-area, doubles, n-gons, z-fight |
+| 16 | Not grounded: bounding box `zmin` off 0, or a named ferrule floats |
+| 17 | Joint fit: hook-bail gap |
+| 18 | Seat: ferrule bite band |
+| 19 | Pot diameter or height off the stated real-world size |