geop-ops-boolean

This page is a reference to the crate; the algorithm is taught in Lecture 22, and this crate is read as an example in Lecture 40.

The operations a program combines and cuts solids with (see geop-core-editor), over the algorithms of geop-lib-booleans.

Boolean unites, intersects or subtracts two solids of the part by name, consuming both; the result is named boolean(B). An empty result is an answer, not an error.

Split cuts a solid with a face standing on its own — and the rest of its sheet — into pieces named split(S,0), split(S,1), …, leaving the face as it was.

Imprint divides two bodies where they cross, keeping both; with a face given, only that face. Section makes the curves where they cross a wire.

SplitFace divides one face along the curves of a sketch, projected onto it along the sketch’s normal, or each point to its nearest on the face, and the solid keeps its shape and volume. It is the kernel’s imprint: the curves are swept into sheets reaching past the face both ways, and those are imprinted on it, so a planar face and a curved one are one path, and a curve reaching past the face is trimmed to it. Every curve of the sketch that is no construction curve divides (Sketch::runs), however they join or cross, and a text’s outlines. A piece split off the face F along the curve c3 of the sketch K is split_face(S,F,K,c3), with ,k for the curve’s k-th stretch across the face; the other piece, and what is left round a curve closing inside the face, keeps the name F; the edge is split_face(S,K,c3). Refused by name: a sketch that misses the face or holds only construction curves, a curve ending inside the face, a curve only joining two of its boundaries, as a line from its outside to a hole does, and a curve running along one of its edges. A wall of a cylinder is four faces, so a loop all round it is four steps.

The same combination done by another operation with the solid it builds — an extrude cutting a pocket, say — is that operation’s Combine, defined in geop-ops-model and applied by combine_tools.

Its examples (examples): split_plate, a plate cut in two by a face extruded from a line, and badge, a disc divided off a plate’s top. The tests of programs uniting extruded and revolved solids — and extruding or revolving up to the next face of solids so united — are here (program_tests.rs): this crate depends on extrude and revolve for its example, not the other way round.