PTC Inc.
B-rep matching for maintaining associativity across CAD interoperation

Abstract:

A method allows transferring references from vertices, edges, and faces of a solid or surface model to an edited model, by finding correspondences between vertices, edges, faces, and bodies of the models. The method begins by quickly finding matching bodies and aligning them, considering factors such as size, complexity, and the location of its vertices, edges, and faces. For every pair of matched bodies, it then matches exactly coincident vertices, edges, and faces. Of the remaining unmatched topology, it matches edges and faces in the new model that overlap those of the old model considerably. It uses near-neighbor structures to speed up the search for correspondences by eliminating old-new pairs of vertices, edges, and faces that do not overlap. Finally, it iteratively matches unmatched vertices, edges, and faces whose adjacent vertices, edges, and faces are in exact correspondence between the old and new models.