Method for performing boolean operations on geometric objects in a computer-aided design system

摘要

In a method for performing Boolean operations (e.g. UNITE) on geometric objects (12,13) to generate a modified geometric object (14) in a computer-aided design system, a face of a first object (12) and a face of a second object (13) are intersected to generate graph edges (15,16) which form edges of the modified geometric object (14). Edges of the first object are intersected with surfaces of the second object to produce intersection points, and surfaces containing the faces of the two objects, respectively, are intersected with each other to produce intersection tracks. If there is an inconsistency between the intersection points and corresponding intersection tracks, i.e., if intersection points which should ideally lie on an intersection track are more than a resolution value (epsilon) apart, a perturbation step is applied to correct the spatial positions of inconsistent intersection points. The perturbation step comprises moving the inconsistent points along edges to a position where geometric consistency is established.