Feature-Based Modeling for Preliminary Design Support

Many years of CAD-application in industry have shown that the design process requires a higher level of supporting the user in his creative work than is permitted by the existing geometric modeling systems. Since “… structuring the thinking of the design engineer into lines, arcs and solid primitives would be equivalent to building a text from more letters instead of words and sentences” [KVYA89], it can be summarized that current generation computer-aided design systems fail to capture the designer’s intent. In order to cure these problems, feature-based design is now recognized as an activity to provide a convenient language for expressing the products using high-level semantic data. Feature-based design is attractive in several ways. For example, feature-based design systems support the users to easily express their design ideas by creating and manipulating features directly, thus eliminating many intermediate steps. A feature-oriented database allows a CAD system to perform different tasks such as design, analysis, process planning, NC programming, because of the knowledge which the features contain to facilitate these tasks.