Extended progressive simplification of feature-based CAD models

It is important that users can progressively simplify a detailed CAD model and create a simplified one for use in various applications. For this purpose, many simplification methods have been proposed, and it is known that feature-based simplification methods are superior for engineering applications. The previous feature-based simplification methods assumed that a feature-based CAD model has a single-branch feature tree, and the type of each feature is either additive or subtractive. However, a feature-based CAD model is often represented as a multi-branch feature tree. Furthermore, the type of a feature may be both additive and subtractive simultaneously. To solve these problems, we present an extended feature-based simplification method. In the proposed method, the modeling sequence of the features from a multi-branch feature tree is determined using the feature dependency graph. The importance of each feature is evaluated, and the features are rearranged by their importance using the proposed extended feature rearrangement algorithm. The feature-based CAD model is finally simplified in a manner where less important features are suppressed until the CAD model reaches the desired level of detail. To demonstrate the proposed method, a prototype system was implemented, and experiments with test cases were performed.