feat(showcase): add rope-bridge (#251)

A rope footbridge was the first unclaimed showcase candidate on the
roadmap. Its failure mode no bounding box can see is the deck shape: two
straight ramps with the same ends and sag pass every envelope check. The
piece fits a least-squares parabola to the plank tops read off the mesh,
and --vee-deck exits 19 on that fit while its sag stays in band.

Also asserts named supports, rope-end and tenon bites, banded plank seats
and lashing hoops, one connected assembly, plumb, plank pitch, rail
height, edge treatment and baked texels per UV island, each with a
falsifier proven on 4.5.11, 5.1.2 and 5.2.1.

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

Author: TMHSDigital

.cursor-plugin/plugin.json

@@ -165,6 +165,7 @@
     "showcase/wooden-ladder",
     "showcase/hay-bale",
     "showcase/crate-stack",
-    "showcase/stone-archway"
+    "showcase/stone-archway",
+    "showcase/rope-bridge"
   ]
 }

CLAUDE.md

@@ -22,7 +22,7 @@ rules/<rule-name>.mdc          - Anti-pattern rules, 9 total
 templates/<template-name>/     - Starter projects, 3 total
 snippets/<snippet-name>.py     - Standalone code patterns, 27 total
 examples/<name>/               - Runnable smoke-gated examples, 59 total (+ gallery.json)
-showcase/<name>/               - Budget-conformance props, 28 pieces (sibling of examples/; see showcase/README.md)
+showcase/<name>/               - Budget-conformance props, 29 pieces (sibling of examples/; see showcase/README.md)
 scripts/build_gallery.py       - Regenerates docs/gallery/ from examples/gallery.json + showcase/gallery.json
 scripts/site/                  - Vendored landing-page build (Jinja2)
 docs/gallery/                  - Committed generated gallery pages + hero renders

README.md

@@ -18,7 +18,7 @@
 </p>
 
 <p align="center">
-  <strong>16 skills</strong> &nbsp;&bull;&nbsp; <strong>9 rules</strong> &nbsp;&bull;&nbsp; <strong>3 templates</strong> &nbsp;&bull;&nbsp; <strong>27 snippets</strong> &nbsp;&bull;&nbsp; <strong>59 examples</strong> &nbsp;&bull;&nbsp; <strong>28 showcase pieces</strong>
+  <strong>16 skills</strong> &nbsp;&bull;&nbsp; <strong>9 rules</strong> &nbsp;&bull;&nbsp; <strong>3 templates</strong> &nbsp;&bull;&nbsp; <strong>27 snippets</strong> &nbsp;&bull;&nbsp; <strong>59 examples</strong> &nbsp;&bull;&nbsp; <strong>29 showcase pieces</strong>
 </p>
 
 <p align="center">
@@ -37,7 +37,7 @@
 
 ## Overview
 
-This repository ships **16 skills, 9 rules, 3 templates, 27 snippets, 59 examples, and 28 showcase pieces** for Blender Python development targeting Blender 5.2 LTS (current stable) with Blender 4.5 LTS fallback support. Blender 5.1 is prior stable.
+This repository ships **16 skills, 9 rules, 3 templates, 27 snippets, 59 examples, and 29 showcase pieces** for Blender Python development targeting Blender 5.2 LTS (current stable) with Blender 4.5 LTS fallback support. Blender 5.1 is prior stable.
 
 The content is consumed by AI coding agents reading these files directly from a checkout — **there is no MCP server in this repository, and none is required**. Cursor applies `rules/*.mdc` automatically wherever their scope globs match and takes skills by name in chat; Claude Code reads `skills/` and `rules/` from the project workspace, or from this repo kept as a referenced checkout. Any agent that can read files in a workspace can use it the same way. There is no build step for the content — edit the Markdown and Python files directly.
 
@@ -106,7 +106,7 @@ per-script exit-code model, are in
 Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](showcase/README.md).
 
 <details>
-<summary><strong>28 showcase pieces</strong> — click to expand the preview grid</summary>
+<summary><strong>29 showcase pieces</strong> — click to expand the preview grid</summary>
 
 <p align="center">
   <a href="showcase/shipping-crate/"><img src="showcase/shipping-crate/preview.webp" width="24%" alt="Shipping crate: a wooden slat crate with iron corner brackets on a dark studio floor, warm wedge on the back wall" /></a>
@@ -137,6 +137,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/hay-bale/"><img src="showcase/hay-bale/preview.webp" width="24%" alt="Hay bale: a bound straw bale with two sisal twine belts on a dark studio floor" /></a>
   <a href="showcase/crate-stack/"><img src="showcase/crate-stack/preview.webp" width="24%" alt="Crate stack: three slatted shipping crates stacked and yawed, each with iron corner straps and runners, on a dark studio floor" /></a>
   <a href="showcase/stone-archway/"><img src="showcase/stone-archway/preview.webp" width="24%" alt="Stone archway: a semicircular masonry arch with coursed piers, projecting imposts, nine voussoirs and a proud keystone, on a dark studio floor" /></a>
+  <a href="showcase/rope-bridge/"><img src="showcase/rope-bridge/preview.webp" width="24%" alt="Rope bridge: a sagging plank deck on foot ropes between two pairs of log posts, with lashed hemp hand ropes, suspenders, and ropes staked to the ground, on a dark studio floor" /></a>
 </p>
 
 [`shipping-crate`](showcase/shipping-crate/) — procedural crate through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets. Falsifier `--skip-decimate` exits 9.
@@ -191,6 +192,8 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`hay-bale`](showcase/hay-bale/) — procedural bound hay bale with sisal twine through the same pipeline. Falsifier `--skip-decimate` exits 9.
 
+[`rope-bridge`](showcase/rope-bridge/) — procedural rope footbridge whose plank deck is fitted to a parabola recomputed from the plank tops, with lashed hand ropes and staked foot ropes, through the same pipeline. Falsifiers `--vee-deck` exits 19, `--float-suspenders` exits 18.
+
 </details>
 
 ## Examples

ROADMAP.md

@@ -133,7 +133,7 @@ Not committed; target list for the next content version. (v0.3.0 shipped the smo
 - ~~Bound hay bale as a game-prop showcase piece~~ **SHIPPED** as `showcase/hay-bale/` — bevelled loaf, end nap, two sisal twine belts; `--skip-decimate` exits 9 on the LOD1 ratio band
 - ~~Stack of shipping crates as a game-prop showcase piece~~ **SHIPPED** as `showcase/crate-stack/` — one generator called three times with a per-instance seed driving yaw and plank widths, crates seated on the lid below; `--same-seed` exits 20 on the per-instance variation budget, `--float-stack` exits 18 on the seat
 - ~~Keystone archway with voussoirs as a game-prop showcase piece~~ **SHIPPED** as `showcase/stone-archway/` — coursed piers, projecting imposts, nine voussoirs, proud keystone; the intrados circle fit is recomputed from vertex positions and `--off-circle` exits 19 on it while leaving every other budget passing
-- Rope bridge (planks, rope rails, sag between anchors) as a game-prop showcase piece
+- ~~Rope bridge (planks, rope rails, sag between anchors) as a game-prop showcase piece~~ **SHIPPED** as `showcase/rope-bridge/` — log posts, through-tenoned sills, twenty planks seated on laid foot ropes, lashed hand ropes, suspenders, staked tie-offs; a least-squares parabola is fitted to the plank tops and `--vee-deck` exits 19 on it with the sag still in band
 - Grain sacks (cloth sacks, some slumped, tied necks) as a game-prop showcase piece
 - Brazier (iron bowl on legs, coals, ash) as a game-prop showcase piece
 - Apothecary shelf (shelf unit, bottles and jars of varied form) as a game-prop showcase piece

docs/gallery/asset-sheets/rope-bridge.webp

@@ -291,7 +291,7 @@ <h1>Examples and Showcase</h1>
             autocomplete="off" spellcheck="false" aria-label="Search examples and showcase pieces" />
           <button class="q-clear" id="qClear" type="button" aria-label="Clear search" hidden>&times;</button>
         </div>
-        <span class="count" id="count" role="status" aria-live="polite">51 examples, 28 showcase pieces</span>
+        <span class="count" id="count" role="status" aria-live="polite">51 examples, 29 showcase pieces</span>
         <div class="density" role="group" aria-label="Card density">
           <button class="density-btn" data-density="compact" type="button" aria-pressed="false">Compact</button>
           <button class="density-btn" data-density="detailed" type="button" aria-pressed="false">Detailed</button>
@@ -1210,6 +1210,17 @@ <h2><a href="stone-archway/">stone-archway</a></h2>
           <a class="card-link" href="stone-archway/">View showcase piece<span class="sr-only"> stone-archway</span> <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
+      <article class="card" data-tags="mesh export showcase">
+        <a class="card-media" href="rope-bridge/" tabindex="-1" aria-hidden="true">
+          <img src="assets/rope-bridge-hero.webp" alt="A wooden rope bridge whose plank deck sags between two pairs of log posts, with hemp hand ropes lashed to the posts, vertical ropes tying rail to deck, and foot ropes run back to ground stakes." loading="lazy" decoding="async" />
+        </a>
+        <div class="card-body">
+          <h2><a href="rope-bridge/">rope-bridge</a></h2>
+          <p class="teaches">A procedural rope footbridge — log posts, through-tenoned sills, twenty planks on two sagging foot ropes, lashed hand ropes, suspenders and staked tie-offs — carried through UVs, bake, LOD, compound collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 8768 tris, two materials with 1356 timber and 3348 rope faces, UVs in 0..1 with zero AABB overlap and 18.8 baked texels per island, outer AABB 4.619×1.073×1.480 m, zmin 0, hygiene 0 including zero coplanar cross-shell pairs, four posts and four stakes grounded, every rope end and sill tenon biting its host, all 20 planks seated 4.0 mm on both foot ropes, 12 lashing turns hooped 2.4 mm, one connected assembly of 60 shells, posts plumb, plank pitch within 0.08 mm, hand ropes 0.87 m over the deck, and every plank top within 2.97 mm of a least-squares parabola with a 0.220 m sag. --vee-deck exits 19 on the parabola fit with its sag still in band; --float-suspenders exits 18 on the contact graph.</p>
+          <a class="card-link" href="rope-bridge/">View showcase piece<span class="sr-only"> rope-bridge</span> <span aria-hidden="true">&rarr;</span></a>
+        </div>
+      </article>
     </div>
     <p class="noresults" id="noResults" hidden>Nothing matches the current filters.
       <button class="chip" id="resetFilters" type="button">Clear search and tags</button></p>
@@ -1239,7 +1250,7 @@ <h2><a href="stone-archway/">stone-archway</a></h2>
       var tagsToggle = document.getElementById('tagsToggle');
       var toTop = document.getElementById('toTop');
       var total = cards.length;
-      var COUNT_LABEL = '51 examples, 28 showcase pieces';
+      var COUNT_LABEL = '51 examples, 29 showcase pieces';
       var LS_KEY = 'bdt-gallery-density';
       var reduced = window.matchMedia && window.matchMedia('(prefers-reduced-motion: reduce)').matches;