Module project 

Normal projection: a wire dropped onto a shape along its faces’ normals.

The projection of a point onto a surface is its foot (the point where the displacement is perpendicular to both tangents), and the projection of a curve is the curve through the feet. That curve almost never has a closed form, so it is sampled, fitted to a stated tolerance, and carries the pcurve fitted with it: same parameter in space and in the chart, which is what makes the result an edge a face can be split along.

Which face a point lands on is decided by measurement, not by order: every face is asked, the nearest foot inside a face’s own trim wins, and a sample no face claims ends the run it was in. So a wire projected onto a solid comes back as one edge per stretch that actually landed, and the stretches that fell off the shape are simply absent.

Structs

Projected

One projected stretch: the edge that was built, and the face it lies on.

Functions

normal_projection

Project every edge of wire onto the faces of target.