Classification of Constrains in STEP and Proposal of their New Expression

ISO 10303 (STEP) is the international standard for computer-interpretable representation and exchange of product model data. STEP has application protocols for each application domain. The model for an AP defines data constructs and its constraints using EXPRESS that is description method of STEP. However, it is difficult to create constraints in EXPRESS for complicated requirements of product specification in real world. In this paper, constraints in released APS have been analyzed and a macro language is proposed to represent constraints more easily.