Algorithms for orthographic views with hidden entities and manufacturing features information for sheet metal parts

This paper describes a procedure derived to generate orthographic views for 3D sheet metal parts with hidden lines information as well as feature information such as holes and forming shapes that are manufactured using punching and special forming tools. As the shape of the part becomes complex with many bends and the number of features in the model becomes larger, the hidden entity processing becomes slower. Optimized processing algorithms are needed to generate the orthographic views with hidden entities and feature information in order to develop competent software packages for the above application. Concepts and techniques to optimize the hidden line processing for complex sheet metal parts having large number of 3D objects, namely, faces, bend lines and other manufacturing features such as holes and forming shapes are described. The processing time required to produce results with desired accuracy has been greatly reduced by grouping the topological entities and processing the projection relationship among the objects of complex parts such as hidden line dependence, hidden line independence, and hidden line interdependence. The feature information are also optimally processed with the projection information of the 3D objects, and final views data will have feature information which are required to carry out easier inspection with original drawing data.