Min/max were seeded at 0, so any geometry not touching the origin got an inflated box, and the first move only updated max (else-if). Rotated canonical drawings are the common trigger: their origin ends up outside the shape, which skewed Part bounds and bbox-based alignment. Track the real extents and keep returning a zero box for empty programs. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>