CURVED SURFACE GENERATING METHOD USING DIGITIZATION DATA

摘要

PURPOSE:To show a curved surface with high accuracy and in a beautiful shape free from a slackened salient angle part by providing the patch lines at both reentrant and salient angle parts of a shape. CONSTITUTION:The digitization data 7 on a three-dimensional shape body 2 obtained by a digitizer 1 is stored in a floppy disk 3 and then sent to an arithmetic unit 4. The unit 4 detects a reentrant angle part 10 of a shape based on the curvature of the point group data and the angle change. Then the unit 4 obtains a unit normal vector N is obtained at each point of the point group data 7. This data 7 is offset downward with use of the vector N and a salient angle part 11 is detected to the offset point group data 7'. The patch lines are provided to both parts 10 and 11 for generation of a curved surface. Then a cutter path is calculated to the curved surface. As a result, an accurate part 11 is obtained and the patch line accuracy is improved.