forked from 1b-agent/opencadstudio-upstream
SECTIONCULL keeps only what the selected section object (or the live section of the space) shows: solids, surfaces and closed meshes are cut to it with the same planes the live section uses, open meshes are clipped face by face, and every other object wholly outside it is erased. Objects across the boundary that cannot be cut stay whole. One undo step. The section's bounding planes are gathered once (section_planes) and shared by the live section and the cull. Refs #1407 Co-Authored-By: Claude Opus 5.5 <[email protected]>