Walk an object subtree and attach an edge overlay to every Mesh found, returning the created
overlays (so callers can dispose them explicitly if they don't clear the whole subtree). Meshes
that already carry an overlay are skipped, so this is safe to call more than once.
Skips the floor and the grid (they're aids, not content) and anything already tagged as an edge.
Walk an object subtree and attach an edge overlay to every
Meshfound, returning the created overlays (so callers can dispose them explicitly if they don't clear the whole subtree). Meshes that already carry an overlay are skipped, so this is safe to call more than once.Skips the floor and the grid (they're aids, not content) and anything already tagged as an edge.