PushBoundingBox left exactly partSpacing between bounding boxes, but the
geometry push inflates offset lines by halfSpacing + chordTolerance per
side (totaling partSpacing + 2*chordTolerance). The 0.002 overlap caused
RayEdgeDistance to return MaxValue for negative t, making the nearest
obstacle invisible and allowing the part to push through it.
Subtract 2*ChordTolerance from the BB push distance so the gap is wide
enough for the offset geometry lines to remain non-overlapping.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>