# Linux 112 — horizontal spline, planned floor profile

## Shape and audits

The passage now follows a dense centripetal spline in XY. Height stays piecewise linear on the planner's horizontal arc-length profile; radius and floor depth blend smoothly. Open-air sections have a floor slab and 1 m side walls, with no roof, and passage interiors take priority over shells. Version is v219; source stamp is `c31c8baca8f8308dca62edc6d286c8e84a8214ede7ca444fdaf337ae743ccee1`.

The audit samples the same generated centreline. No walkability thresholds were loosened: the grade limit remains 15°, headroom remains 0.30 m for Caves and 2.20 m for Lattice, and the shell, mouth, naturalness, and ripple gates remain in place. The owner route has zero blocked, unsupported, or grade-failure samples. The native Caves route passes at 15.000° maximum grade and 0.300 m minimum headroom; native Lattice passes with zero support failures at 10.028° maximum grade and 2.200 m headroom. All three passage interfaces pass shell, mouth, naturalness, and ripple audits. The FI blocked control at passage/1-2 remains detected (16,380 blocked capsule samples); all three blocked controls were detected.

The native Caves field owns its corridor so the transition shell cannot clip it; the passage interior still opens within its own stratum. Lattice's authored support below the floor remains solid. These preserve the same walkability and support requirements.

## Captures

[Capture index](captures/INDEX.md): 110 images verified (60 L109 before, 50 L112 after), covering mouths, 25/50/75% stations, and every open-air section. This includes 32 verified 4 m close-ups (18 before, 14 after) of the outside and interior walls. For the close-ups, the nominal route target snaps to a nearby mesh triangle; the camera remains 4.00 m from the mesh within 0.02 m, with wall-normal alignment at least 0.25.

## Readiness

Five interleaved L80 pairs per cell, all four strata, W8 and W12. Values are median seconds, L109 binary → L112 binary; near is LOD0–2 ready and whole is whole-view ready.

| Stratum | W8 near | W8 whole | W12 near | W12 whole |
|---|---:|---:|---:|---:|
| SW | 0.779 → 0.822 | 1.837 → 1.826 | 0.802 → 0.845 | 1.768 → 1.835 |
| FI | 0.972 → 1.063 | 1.935 → 2.022 | 0.924 → 0.992 | 1.792 → 1.884 |
| TN | 1.021 → 1.092 | 1.869 → 1.970 | 0.931 → 1.023 | 1.758 → 1.866 |
| VS | 0.832 → 0.921 | 1.764 → 1.827 | 0.783 → 0.861 | 1.666 → 1.741 |

L109's prior report recorded W12 near-ready at 0.863 s for FI and 0.895 s for TN. In this matrix the L109 binary remeasured at 0.924 s and 0.931 s; L112 measured 0.992 s and 1.023 s. That is +7.4% and +9.9% against the matched rerun, or +15.0% and +14.3% against the prior report values.

## Candidate lists

Feature and route-segment lists have the same counts. Each cell shows L109 → L112; totals are candidates across profiled tiles.

| Stratum | Profiled tiles | Total candidates | p95 per tile | Maximum per tile |
|---|---:|---:|---:|---:|
| SW | 1,763 → 1,742 | 583 → 4,216 | 3 → 18 | 21 → 185 |
| FI | 1,590 → 1,573 | 1,036 → 7,068 | 4 → 22 | 47 → 420 |
| TN | 1,492 → 1,480 | 869 → 4,784 | 4 → 22 | 23 → 116 |
| VS | 1,660 → 1,660 | 644 → 3,133 | 4 → 18 | 16 → 82 |

## Verification

- Fast tier: PASS, 264 checks.
- Clang/GCC W1/W8/W12 determinism: all 18 runs passed; hashes match within each configuration.
- Linux VFHostEditor build: succeeded with `-NoUBA -MaxParallelActions=4` after timing.
- No commit was created.