The boolean checks its result by meshing both operands and the result, then sampling membership densely where the operands' boxes overlap. The mesh step came from the larger body's size (0.46 mm here), which facets the bar's 3 mm arc so coarsely that two meshes of the same arc disagree over a few percent of the thin overlap box, and a correct cut failed the 0.4 % mismatch limit. The step now also follows the smallest side of the overlap box (2e-3 of it), never finer than 1e-5 of the size, so it only changes where the bodies meet in a region much thinner than they are. truck's first result for the cut is then accepted, and it matches a split of the bar by the tilted plane.
Tests: oblique_cut_through_a_small_arc_matches_a_split replays examples/regressions/oblique_cut_of_cylinder.json and compares with solid.split_body by the same plane (fails on main). The full suite runs no slower.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
