Using Operations on Graphs* Noriyuki FUTAGAMI** and Ken-ichi KOBORI*** Recently, mechanical CAD systems with solid model are used widely in the design process. However, it is not easy to build solid model with some kind of primitive objects and set operations. To solve this problem, we propose an algorithm of automatic conversion from wire-frame data to solid model. Although a large number of studies have been made on this area, previous methods couldn't handle solid objects with freeform

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... es and only treated polyhedra-approximated solid objects. Moreover, some of these approaches require lots of execution time. Because they are based on the combinatorial search algorithm which find actual faces of objects. Our approach solved above two problems on some conditions. It offers high-speed execution and can treat free-form surfaces.