The push algorithm's copy distance formula (bboxDim - slideDistance)
produced distances smaller than the part width when inflated boundary
arc vertices interacted spuriously, causing ~0.05 unit overlaps between
all adjacent grid parts.
Two fixes applied:
- Clamp ComputeCopyDistance to bboxDim + PartSpacing minimum
- Use circumscribed polygons (R/cos(halfStep)) for PartBoundary arc
discretization so chord segments never cut inside the true arc,
eliminating the ChordTolerance offset workaround
Also parallelized three sequential fill loops using Parallel.ForEach:
- FindBestFill angle sweep (up to 38 angles x 2 directions)
- FillPattern angle sweep for group/pair fills
- FillRemainingStrip rotation loop
Added diagnostic logging to HasOverlaps, FindCopyDistance, and
FillRecursive for debugging fill issues.
Test result: 45 parts @ 79.6% -> 47 parts @ 83.1%, zero overlaps.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>