Mechanism of persistent naming topological entity supporting collaborative CAD
支持协同CAD的拓扑实体永久命名机制

Direct referring to topological entity of B-Rep domain in feature's parametric definition domain is inherent limitation of previous persistent naming topological entity method. Therefore, a feature-based solution for topological entity naming was proposed. Firstly, uniform naming method for feature face was established and its name remained invariable during the modeling procedure. Secondly, the expression between topological entity and feature face was established and topological entity expressed by feature face was referred to during the course of feature's parametric definition, and as a result, the problem of persistent naming topological entity for feature-based collaborative CAD was solved. Thirdly, the concept of reference face was proposed and utilized to solve ambiguous referring problem, which arose from topological face splitting, topological edge splitting and multiply intersection edges. Based on the above mentioned, topological face and topological edge matching method was discussed in detail.