A two-stage feature-based design system

Part feature information is used to bridge the gap between design and manufacturing. Several approaches have been used to provide feature information from the CAD system. Of these, the feature-based design system is superior. However, feature information created by the system is limited to feature commands; the system is designed to be independent of the existing CAD system. Here, a two-state feature-based design (primitive design and feature design) concept is proposed. Using this, a designer can take full advantage of the CAD system and the feature-based design concept. A prototype system embedded in AUTOCAD is developed to test the success of the concept. Input is design intention, while outputs are the part's orthographic 3-view, IGES file, and feature information. Features created in the paper are classified into: Pre-defined features, base features, combined features and irregular features. The last three types are not pre-defined; they are extracted and derived during the design cycle. The algorithm for extraction and derivation is developed and discussed.