The check is geometric, not a tuned threshold: on the reported basin (18 mm rim, sloped bowl wall) the rim strip reaches zero width at 15.17 mm and the shell is refused from there on. Tolerances only absorb rounding (scaled to the body size), and at most 2000 straight edges per face are compared pairwise. Arc edges and curved faces are not checked.
This is a guard, not the full fix. Building such a shell needs the offset to change topology: drop the strip that collapses and let its neighbours meet, as offset_body already does for rounds thinner than the move, extended to planar faces. That is substantially more work in the most delicate part of the kernel (rims, ledges, steps, arc-bounded strips) and is left for a separate change; until then the workaround is to model the hollow directly (an offset loft and a box cut).
- solvecraft-cli fuzz / fuzz-one: seeded random modelling sessions (boxes, extruded profiles with arcs, revolves; joins and cuts of boxes, cylinders and spheres, fillets, chamfers, shells, holes, patterns) on a grid that makes coincident faces and tangencies common, every step checked (command ok, every body a sound solid via the new Body::validity, volume moving the right way), plus the boolean volume identity on random primitives; one process per seed with a time limit; failures minimised to scripts
- shell/offset: corners where a curved face meets another at an angle are refined onto the moved surfaces (Newton); edges that are neither lines nor arcs are rebuilt through their moved points; one shell per piece; faces that would cross say so (not supported yet) instead of leaving a cavity inside out; flat revolved faces count as planes; the unhealed body is tried when the healed one fails
- cylinders start their seams at an odd angle (grid-aligned seams broke booleans along them)
- partial revolves of profiles touching the axis build no zero-area face on the axis
- booleans on bodies in several pieces retry a piece at a time
- regression tests for each, and a fixed set of seeds in cargo test
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
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 <[email protected]>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT
CypherNaugh_0x