Implementation of a polygonal algorithm for surface–surface intersections

This paper discussed the problem of finding intersections between surfaces. Surfaces are divided into planar sub-patches, typically triangles. Triangles of one surface are tested for intersection with triangles of the second surface, one by one. The triangles are first projected on a horizontal plane and a vertical plane. The well-known cutting plane method of descriptive geometry is modified and applied to evaluate the line-segment of intersection between two planar triangles. The set of line-segments thus obtained approximate the curve of intersection between the two surfaces.