Fillets (local, loop, rolling ball, corner, variable, chord), chamfers
(cutters, local corners, loops, two sides), shell, draft, offset faces,
split face/body, delete face, patch/copy/stitch/trim/extend and
transforms record their history over [body] while they build: faces
rebuilt from the body's, blends in place of edges (corner patches in
place of the edges at the corner), shell walls as offsets, edges as
pieces of the body's or where two faces meet. Multi-step operations
compose each step. The push-face offset fallback now has history, and
the bore union composes its narrowed tool.
A reflection reorders a body's edges, so transforms now match edges by
identity (mirrored copies reported the wrong edges).
Refs #136
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J53sR6gEaVt56soFDpTck8
blend_corner.rs rebuilds the planar faces at the ends of the filleted edges (three planar faces and three straight edges at each such vertex) and keeps the rest. One round at a vertex ends in the third face's exact section of its cylinder; two rounds with the third edge sharp trim each other (rolling ball: the crease from where their contact lines cross to the third edge for equal radii, else to the smaller round's contact line on the face that ends the larger one, which gets the exact section between); three rounds meet a sphere for equal radii, else a rational degree-4 patch through plane sections of the cylinders, the sections turned so that the cylinders' curvatures agree where two meet on a face and the patch fitted tangent to all three (within 0.01 degrees) and to the face at its closed corner.
kernel::fillet falls back to it when the local blends refuse: an edge that ends on an earlier round (any radius) takes the round off (delete_faces) and blends both edges together, so r3 next to r2 and a third edge into a mitred pair work. delete_faces: a gap stretch along several deleted faces keeps the corners between them (two rounds meeting in a mitre come off back to the sharp corner). splitface::fit is shared for the crease.
Tests: volumes against the strips-minus-overlap reference (exact strips, overlap integrated; checked against an independent 1D integral), the sphere-octant formula for three equal rounds, tangency along the patch, closed meshes, refusals without panics.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
