An Approach to Rapidly Detect the Global Symmetries in Feature-based CAD Models

The existing methods have a low performance of detecting the symmetries in CAD models.Therefore, an approach is proposed to rapidly detect the global reflectional and rotational symmetries in feature-based CAD models by making full use of feature information.In detail, the symmetries of CAD models can be derived by classifying features, sorting feature sets, merging and verifying symmetries of the feature sets.The symmetries of the features can be easily obtained by using feature information.According to the principles of the weak?strong relationships in symmetries, the intermediate detected symmetries can move quickly to the target symmetries of the entire model.Merging and verifying symmetries avoid unnecessary detecting of all the local symmetries to derive the global symmetries.And also, the problems that the symmetries can not be detected by using feature information and how to avoid geometrically detecting symmetries can be efficiently solved.Experimental results show that the global symmetries can be correctly and rapidly detected.