Abstract: According to the TTRS theory, the characteristics of all surfaces in the 3D process model are identified, TTRS of the parts and the geometric and topological information of the corresponding MGDE are obtained, and the process model dimension elements are extracted. According to the relative position of the data, the dimension elements are classified to construct the annotation dimension. Owing to the existence of the redundancies in the elements, the corresponding rules of eliminating the redundant dimension elements are proposed for the three kinds of redundancies, and eventually the elimination is accomplished based on the rules. For the six dimension types, the method for calculating their weights is porposed, and accordingly the dimension order is determined. For the case that there may be redundancy in the generated dimension, the graph theory method is adopted to eliminate the redundant dimensions, and to provide the flow chart of the algorithm for eliminating redundant dimensions. A complete set of dimension is constructed so that the dimensional construction of 3D process model is accomplished. Based on UG/Open Grip, the 3D dimension construction and display module is developed to implement the above algorithm.

Key words: TTRS, three-dimensional annotation, annotation element, annotation dimension, redundancy elimination, graph theory