forked from 1b-agent/fieldcraft-upstream
A face boundary vertex lying (within the weld distance) on an undivided edge of the neighbouring face splits that edge's triangle. Only edges no other triangle uses are looked at, so closed surfaces are unchanged. The half of a crank arm cut on its symmetry plane tessellates with such a junction where the cut face meets the top face; it now meshes (tet and swept hex). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo