[dafioram]

First of four stacked nav PRs, now that hero-orders has merged. Next: nav replay tools (tools/nav-replay), then multi-floor walking and door seams, which still need playtesting.

What was wrong

• Discs, not footprints. Mid-size props (carts, tables, beds) blocked a disc centered on their origin rather than the ground they stand on. A disc overshoots a rectangle's sides and can sit in the wrong place entirely: the farmhouse cart's disc landed on the stairs because it was anchored at the transform origin, not the placed bounding box.
• Tools and game disagreed. The nav tools placed props with a different transform from the game (no root bind pose, no scale_multiplier), so offline replays blocked different ground from what the player saw.
• Slow re-stamping. Marking obstacles tested every triangle on the mesh for every prop, and re-ran on every break (a krug smashing a barrel): a ~200 ms hitch each time.

What this changes

• One footprint. PropFootprint and PropObstacle (Core) compute a prop's footprint from its placed bounding box, detecting which box axis stands up. They mark it as a capsule (fences, walls), a disc grid (wagons, stalls) or its exact rectangle (mid-size props). The game and the tools both mark through them, placing props identically (PropBindPose, moved to Core; IsRigidRootProp and ComputeRootBindPose in RenderHost now delegate to it). Covered by PropFootprintTests.
• Exact rectangles. A rectangle obstacle blocks the triangles it actually covers, and seals a sliver only on a real crossing.
• Faster stamps. Obstacle stamps visit only the triangles under the footprint, via the lookup grid. The break hitch is gone.
• hero-sim. Names the prop blocking each failed walk; --broken leaves out props smashed in the session being replayed; --from/--to replays one click walk from the game log's coordinates; --dump writes the nav mesh and prop footprints around a point as text.

Relation to open work

• qwerin's rest-pose change (open, Doors open within reach, switches in their rest pose, town teleporters ride codingncaffeine/SiegeFX#37) draws switch-type skinned props offset by their rest clip. The game's obstacles follow the drawn placement, but PropBindPose here doesn't know about rest clips, so hero-sim's footprint for those props would sit about a unit off. It touches only a handful of wall switches; I'll follow up once both have landed, moving the rest offset into the shared placement.
• Rebased onto main as of 110940c (with Co-op: joiners see the host, kill what they hit, get hit, and see everyone swing codingncaffeine/SiegeFX#33 to save placements: what became of each map placement in an original save's area #35); applies cleanly with qwerin's open Show levels counting from 0, as the original does #36 and Dev console god mode: the hero takes no damage #37 too.

Testing

• dotnet build SiegeFX.sln -c Release -warnaserror: 0 warnings, 0 errors. dotnet test: all 133 pass.
• Played (on the playtest branch): the farmhouse cart, beds and tables block where they stand; breaking barrels no longer hitches.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FdjaHiBNBYFeCRNMsCg2Bs