Three dimensional geometric modeling system

Abstract

A computer program product and system executing/implementing the same provides a visual depiction of a three dimensional object upon a display device. The program converts feature-based data structure of a designated solid shape to a direct face data structure of the designated solid shape in a manner to keep a history of the three dimensional object consistent with a resulting boundary representation component of the three dimensional object. In converting the feature-based data structure of the designated solid shape to the direct face data structure, the program (1) determines what other solid shapes should be included in the D-Shape; (2) generates a boundary representation for the designated solid shape; (3) uses a topology-changeable local operation to generate a modified boundary representation for the designated solid shape; (4) modifies the history of the three dimensional object; (5) includes the modified boundary representation for the designated solid shape with the data structure for the solid shape; and (6) updates at least part of a history of the three dimensional object. Further, the program product can reconstruct a feature-based data structure from a direct face data structure (D-Shape). In one automatic mode of face selection, the reconstruction process grows a selected face until a recognizable boundary is encountered. The recognizable boundary can be any one of a blend, direct face solid shape, extruded shape, or turn shape.