The Clipper validator flagged valid Opus55 and PEP layouts (P260805-03,
P260626-03). Two causes:
- Arc.ToPoints(circumscribe) scales every vertex out by 1/cos(step/2),
endpoints included, so a 0.03125 corner fillet flattened at 0.01 poked
0.013 past the straight edges it meets. ClipperBridge now flattens itself:
circumscribed arcs keep their endpoints on the arc and put interior
vertices on tangent intersections, with the segment count chosen so the
outward error stays within the tolerance. Arc.ToPoints is unchanged for
its other callers.
- The conservative padding made a layout exactly at the spacing fail.
NestValidator now uses OffsetForValidation: the same conservative
flattening, round joins at a tenth of the tolerance, no padding. Its only
leniency is that join chord error at convex corners.
With both, Opus55 is valid on all 26 benchmark jobs (25 before the
Clipper migration; the old failure was a spike artifact).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>