FEATURE DECOMPOSITION FROM SOLID MODELS FOR AUTOMATIC FLATTENING

The purpose of this research is to propose a method for automatic flat tening of surface features, which are decomposed from a solid model, i nto 2D flat models. In this research, a sheet metal product is describ ed as a solid model. Using a feature decomposition method, the boundar y representation of the solid model is decomposed into surface feature s, and each feature is represented as a face-edge graph. Among the fac es in a feature, an appropriate one is selected as the base face. With the base face as a root, a spanning tree is constructed from the face -edge graph of the feature, and edges for splitting and folding, respe ctively, are identified. Thereafter, the faces, other than the base fa ce, are rotated to the plane of the base face around their folding axe s, and the 2D flat model for a feature can be obtained. According to t he messages identifying edges requiring folding or fastening, manufact urers can produce the feature using the reverse process of flattening. Also, computer graphics is used to animate the feature decomposition and flattening procedures. Copyright (C) 1996 Elsevier Science Ltd