FillGrid had no overlap check after perpendicular tiling of the row
pattern (Step 2), unlike Step 1 which had one. When geometry-aware
FindPatternCopyDistance underestimated row spacing, overlapping parts
were returned unchecked.
Changes:
- Make FillLinear.HasOverlappingParts shape-aware (bbox pre-filter +
Part.Intersects) instead of bbox-only, preventing false positives on
interlocking pairs while catching real overlaps
- Add missing overlap safety check after Step 2 perpendicular tiling
with bbox fallback
- Add diagnostic Debug.WriteLine logging when overlap fallback triggers,
including engine label, step, direction, work area, spacing, pattern
details, and overlapping part locations/rotations for reproduction
- Add FillLinear.Label property set at all callsites for log traceability
- Refactor LinearFillStrategy and ExtentsFillStrategy to use shared
FillHelpers.BestOverAngles helper for angle-sweep logic
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>