#navigation

A side-by-side follow slot must sit perpendicular to the leader's own heading, never perpendicular to the line between the two characters. The line-between-the-pair definition is circular, because it is built from where the follower already is, so each correction chases the last one and the pair collapses to single file. Measured error was 89.6 degrees from the line rule versus 0.2 degrees from the heading rule. Derive the slot axis from the leader's forward vector rotated 90 degrees.

The navmesh voxeliser erodes walkable surfaces by ceil(agentRadius/cellSize) whole cells on each side, so an opening narrower than that budget has no navmesh through it.

A waypoint-graph builder that prunes only isolated nodes still ships fully-connected but walled-off pockets, because graph kept is not graph reachable. In one build, sealed arena corners stranded 27 of 524 nodes as three internal pockets, and about 5% of a max crowd spawned where it could never leave. Filter destination and spawn candidates by connected component, using a flood fill from a known-good root, not by per-node validity checks.