A New Mechanism of Naming Topological Entities for Semantic Feature Operations

Naming topological entities and the validity maintenance of model are two important issues in Computer Aided Design, which can make a semantic feature model conform to all constraints correctly. In this paper, a new mechanism of naming topological entities based on face features is proposed. Based on the corresponding mechanisms for naming topological entities, the methods of coding entities, sub-entities and virtual entities are given. The mechanisms for maintaining the validity of semantic feature operations are described. Sub-edges, sub-faces, virtual faces and virtual sub-edges are applied to process the problem of face obliteration. Sub-edges and virtual edges are used to process the problem of edge obliteration. After the mechanisms for naming topological entities and the methods of validity maintenance are applied to HUSTCAID system, its modeling performance is improved and the feasibility of the proposed mechanisms and methods above is also proved.