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>
Followed up the geometry-gap diagnosis with a wider polygon search.
Result: the cottage's north exterior wall east of doorway DOES exist
in cottage GfxObj 0x01000A2B (polys 0x0032, 0x0033) at
world X=[133.5, 136.3], Y=17.10, Z=[94, 97], normal +Y. Symmetric
polys cover the west side and above the doorway lintel.
The wall SHOULD block sphere at X=133.655 (sphere west edge at 133.175
overlaps wall X range; sphere south edge at 17.11 aligns with wall
at Y=17.10).
New hypothesis: the bug is sphere-vs-corner collision at the meeting
point of cell 0x0150's east wall (X=133.5, Y=[16.5, 17.1]) and the
cottage's north exterior wall (X=[133.5, 136.3], Y=17.10). Cell
transit data shows sphere going from X=132.859 entering alcove to
X=134.022 leaving alcove — sphere reached X=134.022 INSIDE cottage
geometry somehow. The sliding along the slab east face (cn=(+1,0,0)
in captured tick 3254) gradually pushes sphere east. Eventually it
shifts past X=133.5 — the corner where alcove east wall meets cottage
north wall. The corner-handling in our BSP collision may incorrectly
let the sphere slide past, or the alcove cell's east wall and cottage
GfxObj's north wall don't compose correctly at the corner.
Diagnostic apparatus extensions:
- HoltburgLandblockStatics_DatInspection: dumps LandBlockInfo for
landblock 0xA9B4. Shows 114 stabs + 12 buildings. The cottage IS
Building[6] with modelId=0x01000A2B (the GfxObj we already loaded).
- Diagnostic_CottagePolys_NearWalkthroughPosition: widened search
reveals the cottage's full north exterior wall geometry.
- HoltburgCottage_CellPortals_DatInspection: extended with cell
PhysicsPolygon world-frame dump (already in prior commit).
Full updated handoff: docs/research/2026-05-25-door-bug-inside-out-geometry-gap.md
Next-session move: add a "sphere walks +Y from inside alcove at
X near 133" test. If harness slides past the corner like production,
investigate BSPQuery's sphere-vs-edge case. If harness blocks at
corner, the bug is elsewhere (cell 0x0150 BSP not queried, or
cottage GfxObj BSP traversal misses the wall poly).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Added diagnostic apparatus that pinpoints the inside-out walkthrough
as a collision-geometry GAP, not a collision-detection bug.
New tests in DoorBugTrajectoryReplayTests:
- InsideOut_Tick3254_WithCottageWalls_ShouldBlock: hypothesis test that
registered cottage GfxObj 0x01000A2B and replayed the captured tick.
Cottage blocked sphere but with cn=(0,0,1) floor-cap normal, not a
wall normal — first signal that cottage geometry near the sphere
isn't a wall.
- Diagnostic_CottagePolys_NearWalkthroughPosition: dumps cottage polys
near sphere XY=(133.655, 17.59) at any Z. Result: ZERO cottage
polygons in that area. The cottage GfxObj has no geometry where the
sphere walks through.
DoorSetupGfxObjInspectionTests.HoltburgCottage_CellPortals_DatInspection
extended to dump cell 0xA9B40150's 4 physics polygons in world frame:
- floor (Z=94), ceiling (Z=96.5), west wall (X=131.6), east wall (X=133.5)
- All walls only span Y=[16.5, 17.1] — the small doorway alcove volume
- North of Y=17.1, no wall
Captured sphere at (133.655, 17.59) is 0.155 m east of cell east wall
AND 0.49 m north of the wall's Y range. No collision geometry exists
at that XY past Y=17.1. The collision representation has a gap that
the visual cottage covers with a wall.
Production capture confirms the diagnosis: cottage GfxObj fires
[bsp-test] 425 times during inside-out walking — visibility IS
correct post-AddAllOutsideCells fix. Door slab fires 245 times. But
the BSP queries find no polygon at (133.655, 17.6+, 94-95.20). The
slab's east face blocks WEST motion (cn=(+1,0,0) as captured), sphere
free to move +Y past it because no wall is there to block.
Three candidates for next-session investigation:
1. Different cottage GfxObj (Holtburg cottages may be multi-piece)
2. Landblock-baked stab static at the cottage exterior wall location
3. Cottage GfxObj's visual polygons wider than physics polygons (dat fact)
Cheapest next step: add LandblockStatics_DatInspection test that
loads LandBlockInfo 0xA9B4FFFE + iterates StaticObjects + prints
every entity at world XY in [131,135] x [16,19]. Reveals what other
entities live at the cottage doorway.
Full 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>
