CornerSlide_AlcoveEastToCottageNorth_ShouldBlock test:
- Registers cottage GfxObj 0x01000A2B (contains north exterior walls)
- Registers cell 0xA9B40150 BSP via dat-direct load (alcove walls)
- Places sphere at (132.95, 16.8, 94) inside alcove near east wall
- Walks sphere +Y 50 times at walk speed (0.05 m/tick)
Result: sphere STAYS at (132.95, 16.8) for all 50 ticks with collision
normal cn=(0.71, -0.71, 0) — the average of alcove east wall normal
and cottage north wall normal at their meeting corner. The corner
handling works correctly in the harness.
So production's inside-out walkthrough is NOT a geometric or BSP
collision-detection bug. The geometry exists, the collision detection
fires symmetrically at corners. The discrepancy must be a STATE
difference between harness and production:
- Real walkable polygons with edges (harness uses big quad)
- Real terrain (harness uses Z=-1000 stub)
- Accumulated body state across many prior ticks (harness uses fresh)
- Possibly cell ping-pong between 0x0150 and 0x0029 in production
Cottage GfxObj wall polygons at the doorway area confirmed:
- North exterior wall east of doorway: polys 0x0032, 0x0033
X=[133.5, 136.3], Y=17.10, Z=[94, 97], normal +Y
- North exterior wall west of doorway: polys 0x0030, 0x0031, 0x0034,
0x0035 (X<131.6 various ranges)
- Lintel polys above doorway: 0x0037, 0x0038, 0x003A, 0x003B at Z>96.5
Next-session moves (per handoff):
1. Replay captured tick 2586 (where sphere went from cell 0x0150 to
0x0029 at X=134.022, way past alcove east wall). Inspect engine
behavior at exactly that tick's body state.
2. cdb attach to retail at Holtburg cottage doorway — verify whether
retail also lets sphere walk through at off-center, OR blocks
cleanly. If retail also allows walkthrough, this might be
retail-faithful behavior we should accept.
Updated handoff: docs/research/2026-05-25-door-bug-inside-out-geometry-gap.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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