heal_keep evaluated the result's intersection curves outside any guard. truck panics where such a curve no longer evaluates, and the panic escaped boolean_whole, so the retries and fallbacks that would have succeeded never ran. heal_keep now runs under guard and returns the solid unhealed when healing panics (as its doc already promised for failures), and the boolean builds its result body under guard too, so a result that cannot be built counts as a failed attempt.
Tests: shallow_loft_cut_from_the_top_face replays examples/regressions/shallow_loft_cut_from_top_face.json and checks the exact prismatoid volume (fails on main with the panic).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The merged face count no longer joins faces across a Split Face line, and Offset Face's same-surface grouping stops there. A piece whose move the body's topology cannot follow (its neighbour stays put) is swept along its normal and joined on or cut in, giving walls along the split line as in Fusion. Engine test: a split box top counts 7 faces; one half up 5 (27000 mm³), the other down 3 (25200 mm³).
Fixes#12
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT
Split Face records the new edges as polylines on the body (Body::split_lines); the document carries them through later features. STEP export no longer joins pieces of one surface across such a line, and healing (fillets, chamfers, booleans, shell, draft) no longer merges coplanar pieces there, while incidental pieces (boolean leftovers, seam halves) still merge as before. Tests: plane and cylinder splits keep their face count through a STEP round trip (and join without the record), a second split keeps both lines, and an engine test exports a split box after a fillet with 8 faces.
Fixes#11
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT
