# World Assembler L25 — FI helix inside the root

**The ribbon came from two causes.** The shared passage compositor stamped route-mouth tread/support into native air, and the L24 6 m root could not contain this route: its measured centerline reached 5.562 m from the root axis and the mouth bore is 4.5 m. That leaves a nominal `6 - 5.562 - 4.5 = -4.062 m` wall allowance. The axis and units were correct; the support pass ignored surrounding rock, and the root was too small.

L25 gates shared route-mouth support on negative pre-passage density, so it can reinforce existing rock but cannot create a shelf in air. The FI anchor root is now a relief-bearing 13.25 m nominal rock column. I chose a sturdier column with the existing uneven relief over a thin cylinder; it remains column-shaped from outside. The authored spiral stays centered on the root axis.

## Root and passage measurements

Axis `(9.800, 4.571) m`; helix centerline radius `2.999–5.562 m`; bore radius `4.5 m` at the mouth and `3.0 m` through the middle. The conservative wall estimate uses the largest path offset and mouth bore at every height.

| Height (m) | Solid radius min / mean / max (m) |
|---:|---:|
| -68.209 | 12.000 / 12.129 / 12.375 |
| -80.643 | 12.125 / 12.254 / 12.500 |
| -93.595 | 12.500 / 12.672 / 12.875 |
| -106.548 | 12.875 / 13.012 / 13.250 |
| -118.982 | 13.000 / 13.168 / 13.375 |

Minimum measured wall allowance is `1.938 m`, above the existing `1.5 m` reserve.

## Audits

The authored FI Spiral passed on Clang and GCC: 61,173 capsule samples, `blocked=0`, 5,318 support samples, `unsupported=0`, `grade_failures=0`; both route bindings pass, and walkability is 1,135/1,135. Strict layout validation accepted with zero issues; malformed controls were rejected 9/9.

The open-air audit sampled 813,632 passage support points at 0.25 m spacing: `violations=0`, including 11,520 route-support samples. Its L24 ungated-support negative control found 1,438 violations. Naturalness passed with a 0 m flat run and 0.767 m wall-relief peak-to-peak; the L23 smooth-wall negative control was detected at 0 m relief. The capsule, open-air, and naturalness results match between Clang and GCC.

All four style overrides in both recipes passed the open-air audit (zero violations; the L24 control was detected each time). The capsule sweep has failures outside the authored FI Spiral: FI styles 0/1/3 have 7/13/6 blocked samples; SurfaceWorld styles 0/1/2/3 have 4,255/4,071/3,948/4,117 unsupported samples after the safe support gate. Their blocked/grade counts are zero. These are alternate-style walkability failures, not open-air emissions; the canonical FI Spiral and composed SurfaceWorld route pass. The individual logs are `Saved/Linux/linux25-style-*.log`.

L13 parity passed on both compilers: FI 8/8 page pairs, 14 higher-LOD pairs, 782,026 exact-query samples, zero mismatches; SurfaceWorld 5 page pairs, 9 native-only pairs, 14 higher-LOD pairs, 910,651 exact-query samples, zero mismatches. Both had one passing edit pair. L9 uniform-block proofs had zero violations: SurfaceWorld checked 26,977 blocks / 35,906,387 samples; FI used its expected 21,504 fallbacks/unknowns and checked no blocks.

The 24 m crossing passed both compilers and recipes. FI processed 314 moving tiles and SurfaceWorld 432; compiler hashes match per recipe. Crossing whole-view density/mesh/payload/topology hashes (FI 2,370 tiles; SurfaceWorld 2,553):

- FI: `c284b42ced276f4c / f6a90d0027d8d6fe / fdec2a7f61215a1e / 60a99d7c20700cd6`
- SurfaceWorld: `cee18b39a9271559 / c1713be06b92bd8e / fd7954350ebfacfc / c58b075a1b7f2895`

## Determinism and SurfaceWorld

The exact LOD0–8 hash matrix passed at W1/W8/W12 for Clang and GCC: 2,370 whole-view tiles, 960 full-detail tiles, all nine LOD rows and exact-query hashes identical across workers and compilers. Hash vectors are density/mesh/payload/topology:

| Recipe | Whole view (2,370 tiles) | Full detail (960 tiles) | Exact-query density / detail / collision |
|---|---|---|---|
| SurfaceWorld | `8d494f8f843171b2 / 37d21941f6d9cce8 / 47248393fa2f3322 / 36d03d874daef4ae` | `ace56c8f205238ad / a9c603a1248de6b8 / ea55f1f4fcc6a894 / 5ea7bc78a1b678ae` | `c949c4df2ce6f9d9 / 114c501e2d830d94 / e6011d3a248d4849` |
| Floating Islands | `6f0095c01b066744 / efea60f7a9c1d675 / 849c1829e1dcddd5 / 4f7cc65dc1adc234` | `d18e722b37a2479e / 0e410a8e80a3e7f7 / 0751926f0c67d8a4 / f01208bc2f7841ec` | `7b7c50ac24ccadcc / efcba20c0c70c415 / e604823a249029bf` |

Re-run command, with `N=1,8,12`, both compiler binaries, and both recipes:

```sh
timeout 1800s taskset -c 0-11 env LP_NUM_THREADS=12 prlimit --as=6442450944 -- Standalone/bin/linux/VoxelForgeCoreHeadless-linux25-<clang|gcc> --world-assembler-prototype --stream-benchmark --stream-pipeline --stream-hash --force-generate --clip-radius=3 --max-clip-level=8 --far-horizon-lod8-step=0 --workers=N --recipe=<surface-world|floating-islands> Standalone/data/owner_world.json
```

SurfaceWorld away from the passage was directly compared with L23 in L24 and matched at 960 full-detail tiles: `66ac781666579e3e / 914873894a0e38c4 / ec8b03ade039cd56 / a2b621b0321d43dc`. L25 changes only passage/root generation and the shared passage composition region; it does not change the away-from-passage SurfaceWorld field. The L25 full-view hashes above cover a different tile selection from that away-only comparison.

## Captures

The four final captures are 1920×1080 JPEGs under `captures/`, each below 300 KB:

- `fi-pillar-exterior.jpg` (43 KB): wide exterior; thick relief-bearing root, no outside ribbon.
- `fi-pillar-cutaway.jpg` (53 KB): vertical cutaway exposing the helix and central rock.
- `fi-helix-inside.jpg` (37 KB): headlamp on, 90° FOV, camera `(11.495, 7.047, -87.858) m` at resolved route point 200, about 2 m above the tread, aimed down the route tangent. The tight turn leaves a close, wall-heavy view; the cutaway is clearer for the full spiral.
- `sw-arrival-mouth.jpg` (55 KB): headlamp on, 80° FOV, camera `(9.800, 4.571, -133.000) m`, 5.5 m below the lower mouth, looking up into the SW arrival.

## Changes, invariants, and run history

Core evaluator version is 12; FI geometry version is 7; resolved-layout schema V3 is unchanged. Source changes are in the Core passage planner/compositor, FI root geometry, and the standalone audit/hash reporting. `ARCHITECTURE.md` §8.43 and `CODEMAP.md` §3.26 document the change. The only Unreal edit is the adapter's FI geometry-version assignment (`geometryVersion = 7`); Unreal was unavailable, so that adapter edit was not compiled here.

L3 FP-contract preamble/self-test, L4 `FLazy`, L7 shared cache, L9/L12 proofs, L11 readiness/crash fix, L13 route binding, L18/L19 shared ceiling, L21/L22 layout and bands, L23/L24 passages, ARCHITECTURE §8.10, and CLAUDE.md async rules remain intact. No commit, push, or stash was made.

Failed or retried runs:

- The first scene export omitted `--render-distance-chunks=0`; it expanded to 593,068 tiles / about 640 MB and was stopped before 15 minutes, then its partial export was removed. A render-distance-48 retry returned 844 plane-dominated tiles / 31 MB and was discarded. Clipmap-only (195 tiles) and focused 27-tile detail exports succeeded.
- Two extra GCC audit invocations exited 2 because the headless binary needs the owner JSON as a positional path; the corrected invocation with `Standalone/data/owner_world.json` passed. The requested six-worker/compiler/recipe hash matrix itself passed.
- Early interior camera trials missed the resolved helix centerline and showed wall-only frames; the final interior frame uses a point extracted from the current resolved layout. No build or audit exceeded 30 minutes, and no step was left stuck for 15 minutes.

## Orchestrator review (Claude) — side branch, not merged yet

- The FI helix fix is confirmed by my capture review: `fi-pillar-exterior.jpg` shows a solid relief-bearing
  column with no outside ribbon, and `fi-pillar-cutaway.jpg` shows the helix inside it.
- **Regression that blocks merge:** the support gate makes non-FI passages unwalkable. With the SurfaceWorld
  recipe (the owner world's TunnelNetwork strate above SurfaceWorld), every style has ~4,000 unsupported
  capsule samples (L24: 0). FI styles 0/1/3 have blocked samples. The owner world's real TN→SW passage is
  affected, so a player can fall through it.
- Kept on side branch `wip/l25-helix`; `assembler/world` stays at L24 (`cb9236c`) until L26 makes every style
  in both recipes pass with 0 blocked / 0 unsupported / 0 open-air violations.
- Design decision (owner delegated decisions to me, 2026-10-21): passages are tunnels in rock. The planner keeps
  the path inside solid ground where possible; unavoidable open-air crossings get a natural, grounded rock
  bridge (thick, relief, connected to rock on both ends), never a floating tread.