Abstract: A new algorithm for calculating the intersection curves between parametric surface and a plane is presented. Based on the half - space properties of plane, the intersection problem with two directional linear interpolation within parametric domain is studied, in which some simple processes, such as scattering, judgement, comparision and sorting are applied. The algorithm can efficiently copy with the uncontinuety and losses of intersection curves, and also proved to be reliable, precise and widely applicable in NC automatic programming. It is significant to improve the precision of NC machining for parametric surfaces of aerospace, aviation and automobile.

Key words: Half-space properties, Intersection algorithm, Two directional linear interpolation NC programming