ComputeNormal assumed CW winding for all contours. For CCW-wound cutouts, line normals pointed to the material side instead of scrap, placing lead-ins on the wrong side. Now accepts a winding parameter: lines flip the normal for CCW winding, and arcs flip when arc direction differs from contour winding (concave feature detection). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>