The room-wins rule cost +55% static / +36% moving worker CPU because every sample re-answered the room-mouth question. A bounded exact memo around BuildRoomMouth (4096 sets x 4 ways, 7.49 MiB, keyed on every geometry-affecting room/tunnel input) removes that: hit rate 99.91% static / 99.89% moving, and VF_FindRoomFloorCrossingWorld (19.5%/17.1% inclusive), VF_FindRoomMouthBoundary (16.0%/14.0%) and VF_EvaluateRoomLandingDensity leave the sampler's top 30 entirely.
vs the tip DLL (bf9384a runtime), same staged owner map: worker sum 29.003 s vs 30.749 s static (-5.7%), 57.232 s vs 60.923 s moving (-6.1%), request p95 -3.3% / -8.4%. Geometry unchanged by construction: canonical hash 86A99075, 64/64 tile hashes, OBJ SHA 7E0D8109..C543, identical across a repeat run and with -voxel.CrtFma3=0. Walk Connected 42,870 / 17,413; tunnel-attributed solid inside rooms 0; mouth amplitude 1.4903 cm; TilePostReachProof and DetSinCos pass. The crossing test was not rerun (the memo returns the same values; its PASS stands at 248.43 m / 26.584 s).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ