Point-oriented persistent identification of entities for exchanging parametric CAD data

Abstract

TransCAD is a specialized CAD system for data exchange that is based on a set of standard modeling commands through which macro file of a CAD model is exchanged. A problem in CAD data exchange has been the consistency of persistent identifiers among different commercial CAD systems. Identifiers serve the purpose of unique and unambiguous naming for topological entities. The current identification approach experiences problems that are caused due to its topology-based mechanism. An identification approach based on a point that has both geometry and topology information is proposed. The names of topological entities i.e. face, edge and vertex are based on the names of their adjacent points. A point-based name is optimized to have most of the data needed for the mapping of arguments used in entity selection commands. This point-oriented naming method is implemented and verified in TransCAD. It is possible to resolve the current issues through a hybrid reference module. The proposed method may then be used in the development of translators for exchanging parametric CAD data.