A straight-edge fillet required each end of the edge to meet exactly one more
face, square to the edge. Now an end may meet one planar face at any angle
(the round ends in it along an exact ellipse, the cross-section slid along
the edge onto the plane) or two planar faces meeting at the end vertex: the
round ends across both and cuts back the edge between them where its
cylinder crosses it (Vida, Martin and Varady 1994: trimlines joined across
existing faces). The cylinder is swept to cover both trimmed ends. Square
ends are built as before.
This rounds the mitres where two chamfers meet at a plate's corner, and a
concave edge where a post stands on a plate (the round's end caps extend
the post's end faces); both were refused.
Fixes#215
Claude-Session: https://claude.ai/code/session_01TWc1smHYwTSVrVc8SNvS44
Co-authored-by: Claude Opus 5.5 <[email protected]>
