A cut whose tool ends exactly on a face of the target (a hole cut from a pocket's floor up to the
plate's top face) could come out of the general boolean with the target's face whole over the hole
and the tool's end face under it: a skin of no thickness that keeps the hole closed. No volume
shows it and the sampled membership checks see the hole either way, so the result was kept. The
result check now refuses a body with a planar face lying back to back on another of its own planar
faces with nothing behind part of it (`coplanar::has_skin`), and the retries take the cut.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Erlis VidalandClaude Opus 5.5
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