Kernel (surfaces):
- Bodies with an open shell are surface bodies (Body::is_surface).
- patch_region: a planar patch of a sketch region. patch_edges: a planar
patch filling a closed loop of a body's edges.
- copy_faces: faces copied out as a surface.
- stitch: sew surfaces along coinciding edges, turning faces to agree; the
result is a solid when it closes.
- trim: cut a surface by a plane or face and keep one side.
- thicken: offset planar and circular-cylindrical faces along their
normals (one side or symmetric) into a solid. Plane copies slide;
cylinder copies scale about the axis, exact for NURBS circles. Free
edges get ruled walls. Faces meeting at a sharp edge are refused.
Doc features Patch, Stitch, Thicken (with operations) and SurfaceTrim;
engine commands FusionSurfacePatchCommand, FusionSurfaceStitchCommand,
FusionSurfaceThickenCommand and FusionSurfaceTrimCommand.
Tests (volumes):
- A 10x10 patch thickened by 2 gives 200, also symmetric.
- Half a cylinder side thickened outward gives half a ring; both halves
inward give the full ring.
- Six faces of a box stitched back give 6000; an open box with its top
patched from the edges, stitched, gives 6000.
- Trim keeps 30 or 70 of 100.
- Engine: patch, trim, thicken gives 140.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
split_body(body, tool) divides every face where the tool meets it and
closes each side with the piece of the tool surface inside the body.
- Patches have outer loops and holes.
- Bands go round a cylinder or another surface of revolution.
- Each side falls apart into its connected parts.
- A body the tool misses comes back whole.
Faces that are B-spline sheets but really planes or circular cylinders
(extruded faces) split as the whole plane or cylinder: the tool is
extended, and the field is exact and cheap.
Tests (volumes): a box split by a plane (2400/3600); a holed plate split
through its hole into two equal halves; a box split by a cylinder's side
into the core (pi*16*30) and the rest; a plane that misses.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
split_faces(body, faces, tool) divides the chosen faces where the tool
meets them and leaves the solid unchanged. It handles:
- lines across a face;
- closed lines inside a face (a disc inside a ring);
- lines that run into a hole (the face is divided around it).
Edges the line ends on are cut in every face that uses them. The tool's
zero set is traced on a finely divided triangulation of the face, each
point is placed exactly on the surface by bisection in its parameters,
the ends are placed exactly on the boundary edges, and a cubic is fitted
through the points (a line when they are straight).
Tests: a box top split by a plane (areas 80/120, later booleans still
work); a cylinder side split by a sketch line; a cylinder top split in
ring and disc by a smaller cylinder's face; a plate top split through
its hole into two equal halves; a tool that misses is an error. Volume
and area are unchanged in every case.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
