6 A Fine - grain and Feature - oriented Product Database for Collaborative Engineering

Traditionally, product databases are either purely geometric or meta-linked to CAD files. The first type lacks feature semantics and hence is too rigid for collaborative engineering. The second type is dependent on CAD files which are system sensitive and has too large information grain size that makes information sharing and engineering collaboration difficult. This chapter introduces a fine-grain and feature-oriented product database design. It is ideal to support Web-enabled collaborative engineering services. For this purpose, a four-layer information integration infrastructure is proposed. A solid modeler is incorporated to provide low-level geometrical modeling services. The novelty of this research includes three aspects: (1) a generic feature definition for different applications in the form of EXPRESS-schemas; (2) the integration of a solid modeler with feature-oriented database by mapping from EXPRESS-defined feature model to the runtime solid modeler data structure as well as to the targeted database schema; and (3) Modelerbased generic algorithms for feature validation and manipulation via the database. A modeler-supported history-independent approach is developed for feature model re-evaluation.