RECONSTRUCTION OF CURVILINEAR MANIFOLD OBJECTS FROM ORTHOGRAPHIC VIEWS

An efficient algorithm to reconstruct objects from engineering drawing s is proposed. All possible manifold objects are identified from drawi ngs composed of orthographic views or auxiliary views. The objects are bounded by planes and quadratic surfaces and axes of quadratic surfac es should parallel to directions of projections. The algorithm first b uilds wireframes from drawings. Faces are created by searching loops i n the wireframe. Depth information including solid curves and broken c urves in the drawings are completely utilized to remove pathological e dges and faces. Then the non-coexistent faces in the wireframe are rem oved by a divide-and-conquer algorithm in order that a manifold object would be composed of rest faces. Objects are constructed through the Euler operators in a non-manifold geometric model. Several non-trivial examples are given to demonstrate the completeness of the algorithm. (C) 1996 Elsevier Science Ltd