Method and apparatus for creating a two-dimensional projection diagram of a three-dimensional shape model using a computer

摘要

PURPOSE:To enable high-accuracy dimension conversion by finding the inner products of a projection-directional vector and normal vectors stood on the curved surface of the three-dimensional model, and generating a two-dimensional curved line which connects points where the internal product is nearly zero as the two-dimensional projection contour line of the three-dimensional body. CONSTITUTION:A CAD/CAM system consists of a free curved surface generation processing part 1, a free curved surface cutting tool path generation part 2, an NC milling machine 3, an input device 4, and a display 5. Here, the individual internal products K of the vector J in the projection direction and normal vectors N stood on the curved surface of the three-dimensional shape model are calculated and the points M on the curved surface where the inner product value is nearly zero are extracted to generate the two-dimensional curve S which connecting the extracted points. Consequently, the high-accuracy dimension conversion is performed.