passages: XY-smooth spline with planned height profile + open-air half-pipe (L112, v219)

Dense centripetal spline in XY, height piecewise-linear on the planner's certified profile,
radius/floor depth blended; open air = floor slab + 1 m side walls, no roof; audits sample the
generated centreline. All walk audits pass (grades <= 15 deg, headroom, shell, mouths, ripple);
Clang/GCC W1/W8/W12 deterministic; fast tier PASS; Linux UE builds. Chevron rings gone.
Open issues: jagged spikes along the half-pipe wall tops, visible step lines on the trough
floor; near-ready +7..+10% vs L109 (candidate list p95 4 -> 22). Not merged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Research/WorldAssemblerM3/Linux112/captures/INDEX.md

@@ -0,0 +1,119 @@
+# L112 passage captures
+
+Each PNG was rendered from its own exported mesh. The renderer reported visible triangles, and each decoded image met the pixel coverage floor. `low_contrast_geometry_visible` marks images that met this floor below the preferred contrast target.
+
+## Before
+
+- [upper-mouth](before/passage-0-1-0-upper-mouth.png) — passage/0-1/0; 253282 visible triangles
+- [lower-mouth](before/passage-0-1-0-lower-mouth.png) — passage/0-1/0; 559326 visible triangles
+- [25%](before/passage-0-1-0-station-25.png) — passage/0-1/0; 145630 visible triangles
+- [50%](before/passage-0-1-0-station-50.png) — passage/0-1/0; 430386 visible triangles
+- [75%](before/passage-0-1-0-station-75.png) — passage/0-1/0; 294374 visible triangles
+- [section-1/view-1](before/passage-0-1-0-openair-1-view-1.png) — passage/0-1/0 **OPEN AIR**; 289074 visible triangles
+- [section-1/view-2](before/passage-0-1-0-openair-1-view-2.png) — passage/0-1/0 **OPEN AIR**; 298057 visible triangles
+- [section-1/view-3](before/passage-0-1-0-openair-1-view-3.png) — passage/0-1/0 **OPEN AIR**; 322309 visible triangles
+- [section-1/4m-outside](before/passage-0-1-0-openair-1-4m-outside.png) — passage/0-1/0; 289074 visible triangles
+- [section-1/4m-interior-wall](before/passage-0-1-0-openair-1-4m-interior-wall.png) — passage/0-1/0; 322309 visible triangles
+- [section-2/view-1](before/passage-0-1-0-openair-2-view-1.png) — passage/0-1/0 **OPEN AIR**; 283642 visible triangles
+- [section-2/view-2](before/passage-0-1-0-openair-2-view-2.png) — passage/0-1/0 **OPEN AIR**; 316771 visible triangles
+- [section-2/view-3](before/passage-0-1-0-openair-2-view-3.png) — passage/0-1/0 **OPEN AIR**; 322309 visible triangles
+- [section-2/4m-outside](before/passage-0-1-0-openair-2-4m-outside.png) — passage/0-1/0; 283642 visible triangles
+- [section-2/4m-interior-wall](before/passage-0-1-0-openair-2-4m-interior-wall.png) — passage/0-1/0; 363071 visible triangles
+- [section-3/view-1](before/passage-0-1-0-openair-3-view-1.png) — passage/0-1/0 **OPEN AIR**; 262299 visible triangles
+- [section-3/view-2](before/passage-0-1-0-openair-3-view-2.png) — passage/0-1/0 **OPEN AIR**; 310919 visible triangles; low_contrast_geometry_visible
+- [section-3/view-3](before/passage-0-1-0-openair-3-view-3.png) — passage/0-1/0 **OPEN AIR**; 363071 visible triangles
+- [section-3/4m-outside](before/passage-0-1-0-openair-3-4m-outside.png) — passage/0-1/0; 298863 visible triangles
+- [section-3/4m-interior-wall](before/passage-0-1-0-openair-3-4m-interior-wall.png) — passage/0-1/0; 340799 visible triangles
+- [section-4/view-1](before/passage-0-1-0-openair-4-view-1.png) — passage/0-1/0 **OPEN AIR**; 378007 visible triangles
+- [section-4/view-2](before/passage-0-1-0-openair-4-view-2.png) — passage/0-1/0 **OPEN AIR**; 471132 visible triangles
+- [section-4/view-3](before/passage-0-1-0-openair-4-view-3.png) — passage/0-1/0 **OPEN AIR**; 382187 visible triangles
+- [section-4/4m-outside](before/passage-0-1-0-openair-4-4m-outside.png) — passage/0-1/0; 309174 visible triangles
+- [section-4/4m-interior-wall](before/passage-0-1-0-openair-4-4m-interior-wall.png) — passage/0-1/0; 382187 visible triangles
+- [upper-mouth](before/passage-1-2-0-upper-mouth.png) — passage/1-2/0; 570417 visible triangles; low_contrast_geometry_visible
+- [lower-mouth](before/passage-1-2-0-lower-mouth.png) — passage/1-2/0; 511318 visible triangles
+- [25%](before/passage-1-2-0-station-25.png) — passage/1-2/0; 661032 visible triangles
+- [50%](before/passage-1-2-0-station-50.png) — passage/1-2/0; 602996 visible triangles
+- [75%](before/passage-1-2-0-station-75.png) — passage/1-2/0; 615520 visible triangles
+- [section-1/view-1](before/passage-1-2-0-openair-1-view-1.png) — passage/1-2/0 **OPEN AIR**; 629052 visible triangles
+- [section-1/view-2](before/passage-1-2-0-openair-1-view-2.png) — passage/1-2/0 **OPEN AIR**; 588414 visible triangles
+- [section-1/view-3](before/passage-1-2-0-openair-1-view-3.png) — passage/1-2/0 **OPEN AIR**; 616234 visible triangles
+- [section-1/4m-outside](before/passage-1-2-0-openair-1-4m-outside.png) — passage/1-2/0; 629052 visible triangles
+- [section-1/4m-interior-wall](before/passage-1-2-0-openair-1-4m-interior-wall.png) — passage/1-2/0; 573086 visible triangles
+- [upper-mouth](before/passage-2-3-0-upper-mouth.png) — passage/2-3/0; 59562 visible triangles
+- [lower-mouth](before/passage-2-3-0-lower-mouth.png) — passage/2-3/0; 294522 visible triangles; low_contrast_geometry_visible
+- [25%](before/passage-2-3-0-station-25.png) — passage/2-3/0; 55484 visible triangles; low_contrast_geometry_visible
+- [50%](before/passage-2-3-0-station-50.png) — passage/2-3/0; 457754 visible triangles
+- [75%](before/passage-2-3-0-station-75.png) — passage/2-3/0; 475706 visible triangles
+- [section-1/view-1](before/passage-2-3-0-openair-1-view-1.png) — passage/2-3/0 **OPEN AIR**; 104612 visible triangles
+- [section-1/view-2](before/passage-2-3-0-openair-1-view-2.png) — passage/2-3/0 **OPEN AIR**; 81078 visible triangles
+- [section-1/view-3](before/passage-2-3-0-openair-1-view-3.png) — passage/2-3/0 **OPEN AIR**; 94962 visible triangles; low_contrast_geometry_visible
+- [section-1/4m-outside](before/passage-2-3-0-openair-1-4m-outside.png) — passage/2-3/0; 104612 visible triangles; low_contrast_geometry_visible
+- [section-1/4m-interior-wall](before/passage-2-3-0-openair-1-4m-interior-wall.png) — passage/2-3/0; 99334 visible triangles
+- [section-2/view-1](before/passage-2-3-0-openair-2-view-1.png) — passage/2-3/0 **OPEN AIR**; 475688 visible triangles
+- [section-2/view-2](before/passage-2-3-0-openair-2-view-2.png) — passage/2-3/0 **OPEN AIR**; 479134 visible triangles
+- [section-2/view-3](before/passage-2-3-0-openair-2-view-3.png) — passage/2-3/0 **OPEN AIR**; 479134 visible triangles
+- [section-2/4m-outside](before/passage-2-3-0-openair-2-4m-outside.png) — passage/2-3/0; 475688 visible triangles
+- [section-2/4m-interior-wall](before/passage-2-3-0-openair-2-4m-interior-wall.png) — passage/2-3/0; 486364 visible triangles
+- [section-3/view-1](before/passage-2-3-0-openair-3-view-1.png) — passage/2-3/0 **OPEN AIR**; 485216 visible triangles
+- [section-3/view-2](before/passage-2-3-0-openair-3-view-2.png) — passage/2-3/0 **OPEN AIR**; 479198 visible triangles
+- [section-3/view-3](before/passage-2-3-0-openair-3-view-3.png) — passage/2-3/0 **OPEN AIR**; 490436 visible triangles; low_contrast_geometry_visible
+- [section-3/4m-outside](before/passage-2-3-0-openair-3-4m-outside.png) — passage/2-3/0; 485216 visible triangles
+- [section-3/4m-interior-wall](before/passage-2-3-0-openair-3-4m-interior-wall.png) — passage/2-3/0; 490436 visible triangles
+- [section-4/view-1](before/passage-2-3-0-openair-4-view-1.png) — passage/2-3/0 **OPEN AIR**; 475298 visible triangles
+- [section-4/view-2](before/passage-2-3-0-openair-4-view-2.png) — passage/2-3/0 **OPEN AIR**; 495856 visible triangles
+- [section-4/view-3](before/passage-2-3-0-openair-4-view-3.png) — passage/2-3/0 **OPEN AIR**; 496236 visible triangles; low_contrast_geometry_visible
+- [section-4/4m-outside](before/passage-2-3-0-openair-4-4m-outside.png) — passage/2-3/0; 475298 visible triangles
+- [section-4/4m-interior-wall](before/passage-2-3-0-openair-4-4m-interior-wall.png) — passage/2-3/0; 475316 visible triangles
+
+## After
+
+- [upper-mouth](after/passage-0-1-0-upper-mouth.png) — passage/0-1/0; 244874 visible triangles
+- [lower-mouth](after/passage-0-1-0-lower-mouth.png) — passage/0-1/0; 551596 visible triangles
+- [25%](after/passage-0-1-0-station-25.png) — passage/0-1/0; 135136 visible triangles
+- [50%](after/passage-0-1-0-station-50.png) — passage/0-1/0; 316508 visible triangles
+- [75%](after/passage-0-1-0-station-75.png) — passage/0-1/0; 257040 visible triangles
+- [section-1/view-1](after/passage-0-1-0-openair-1-view-1.png) — passage/0-1/0 **OPEN AIR**; 278629 visible triangles
+- [section-1/view-2](after/passage-0-1-0-openair-1-view-2.png) — passage/0-1/0 **OPEN AIR**; 287396 visible triangles
+- [section-1/view-3](after/passage-0-1-0-openair-1-view-3.png) — passage/0-1/0 **OPEN AIR**; 311780 visible triangles
+- [section-1/4m-outside](after/passage-0-1-0-openair-1-4m-outside.png) — passage/0-1/0; 278629 visible triangles
+- [section-1/4m-interior-wall](after/passage-0-1-0-openair-1-4m-interior-wall.png) — passage/0-1/0; 311780 visible triangles
+- [section-2/view-1](after/passage-0-1-0-openair-2-view-1.png) — passage/0-1/0 **OPEN AIR**; 278629 visible triangles
+- [section-2/view-2](after/passage-0-1-0-openair-2-view-2.png) — passage/0-1/0 **OPEN AIR**; 311780 visible triangles
+- [section-2/view-3](after/passage-0-1-0-openair-2-view-3.png) — passage/0-1/0 **OPEN AIR**; 311780 visible triangles
+- [section-2/4m-outside](after/passage-0-1-0-openair-2-4m-outside.png) — passage/0-1/0; 278629 visible triangles
+- [section-2/4m-interior-wall](after/passage-0-1-0-openair-2-4m-interior-wall.png) — passage/0-1/0; 350192 visible triangles
+- [section-3/view-1](after/passage-0-1-0-openair-3-view-1.png) — passage/0-1/0 **OPEN AIR**; 210501 visible triangles
+- [section-3/view-2](after/passage-0-1-0-openair-3-view-2.png) — passage/0-1/0 **OPEN AIR**; 189354 visible triangles
+- [section-3/view-3](after/passage-0-1-0-openair-3-view-3.png) — passage/0-1/0 **OPEN AIR**; 189354 visible triangles
+- [section-3/4m-outside](after/passage-0-1-0-openair-3-4m-outside.png) — passage/0-1/0; 156696 visible triangles
+- [section-3/4m-interior-wall](after/passage-0-1-0-openair-3-4m-interior-wall.png) — passage/0-1/0; 156658 visible triangles
+- [upper-mouth](after/passage-1-2-0-upper-mouth.png) — passage/1-2/0; 595932 visible triangles
+- [lower-mouth](after/passage-1-2-0-lower-mouth.png) — passage/1-2/0; 546268 visible triangles
+- [25%](after/passage-1-2-0-station-25.png) — passage/1-2/0; 655074 visible triangles
+- [50%](after/passage-1-2-0-station-50.png) — passage/1-2/0; 604662 visible triangles
+- [75%](after/passage-1-2-0-station-75.png) — passage/1-2/0; 612135 visible triangles
+- [section-1/view-1](after/passage-1-2-0-openair-1-view-1.png) — passage/1-2/0 **OPEN AIR**; 623352 visible triangles
+- [section-1/view-2](after/passage-1-2-0-openair-1-view-2.png) — passage/1-2/0 **OPEN AIR**; 576164 visible triangles; low_contrast_geometry_visible
+- [section-1/view-3](after/passage-1-2-0-openair-1-view-3.png) — passage/1-2/0 **OPEN AIR**; 570605 visible triangles
+- [section-1/4m-outside](after/passage-1-2-0-openair-1-4m-outside.png) — passage/1-2/0; 623352 visible triangles
+- [section-1/4m-interior-wall](after/passage-1-2-0-openair-1-4m-interior-wall.png) — passage/1-2/0; 612135 visible triangles
+- [section-2/view-1](after/passage-1-2-0-openair-2-view-1.png) — passage/1-2/0 **OPEN AIR**; 628316 visible triangles
+- [section-2/view-2](after/passage-1-2-0-openair-2-view-2.png) — passage/1-2/0 **OPEN AIR**; 585440 visible triangles
+- [section-2/view-3](after/passage-1-2-0-openair-2-view-3.png) — passage/1-2/0 **OPEN AIR**; 613722 visible triangles
+- [section-2/4m-outside](after/passage-1-2-0-openair-2-4m-outside.png) — passage/1-2/0; 585802 visible triangles
+- [section-2/4m-interior-wall](after/passage-1-2-0-openair-2-4m-interior-wall.png) — passage/1-2/0; 574472 visible triangles
+- [upper-mouth](after/passage-2-3-0-upper-mouth.png) — passage/2-3/0; 59568 visible triangles
+- [lower-mouth](after/passage-2-3-0-lower-mouth.png) — passage/2-3/0; 294004 visible triangles; low_contrast_geometry_visible
+- [25%](after/passage-2-3-0-station-25.png) — passage/2-3/0; 55514 visible triangles; low_contrast_geometry_visible
+- [50%](after/passage-2-3-0-station-50.png) — passage/2-3/0; 458230 visible triangles
+- [75%](after/passage-2-3-0-station-75.png) — passage/2-3/0; 475838 visible triangles
+- [section-1/view-1](after/passage-2-3-0-openair-1-view-1.png) — passage/2-3/0 **OPEN AIR**; 104612 visible triangles
+- [section-1/view-2](after/passage-2-3-0-openair-1-view-2.png) — passage/2-3/0 **OPEN AIR**; 76426 visible triangles
+- [section-1/view-3](after/passage-2-3-0-openair-1-view-3.png) — passage/2-3/0 **OPEN AIR**; 94962 visible triangles
+- [section-1/4m-outside](after/passage-2-3-0-openair-1-4m-outside.png) — passage/2-3/0; 104612 visible triangles; low_contrast_geometry_visible
+- [section-1/4m-interior-wall](after/passage-2-3-0-openair-1-4m-interior-wall.png) — passage/2-3/0; 94962 visible triangles; low_contrast_geometry_visible
+- [section-2/view-1](after/passage-2-3-0-openair-2-view-1.png) — passage/2-3/0 **OPEN AIR**; 476214 visible triangles
+- [section-2/view-2](after/passage-2-3-0-openair-2-view-2.png) — passage/2-3/0 **OPEN AIR**; 479366 visible triangles
+- [section-2/view-3](after/passage-2-3-0-openair-2-view-3.png) — passage/2-3/0 **OPEN AIR**; 479366 visible triangles
+- [section-2/4m-outside](after/passage-2-3-0-openair-2-4m-outside.png) — passage/2-3/0; 476214 visible triangles
+- [section-2/4m-interior-wall](after/passage-2-3-0-openair-2-4m-interior-wall.png) — passage/2-3/0; 486990 visible triangles