In this paper we describe algorithms for generating NC tool paths for machining of arbitrarily shaped 2 l/2 dimensional pockets with arbitrary islands. These pocketing algorithms are based on a new offsetting algorithm presented in this paper. Our offsetting algorithm avoids costly two-dimensional Boolean set operations, relatively expensive distance calculations, and the overhead of extraneous geometry, such as the Voronoi diagrams, used in other pocketing algorithms.

An algorithm for generating tool positions for three-axis mill cutter paths on parametric surfaces is presented. The novelty of this algorithm is in its use of a surface subdivision technique as an alternative to the traditional APT-style iterative approaches based on local tangent-plane extensions. The algorithm presented provides global interference checking and does not exhibit the convergence problems of the traditional approaches.>