METHOD FOR COMPRESSING AND GENERATING CURVED SURFACE OF POLYGON DATA

摘要

PROBLEM TO BE SOLVED: To compress polygon data by deforming a triangular-shaped polygon into a rectangular-shaped polygon and to convert the compressed polygon data into a group of smooth curved surfaces by expressing the data by using a Gregory curved surface. SOLUTION: Rectangular shape is formed by joining the triangular shape of the polygon data adjacent to each other (20), a larger triangular area (coupled area) is created by joining the generated minimum rectangles (40) and furthermore, the coupled area is magnified by successively joining the coupled area (60). Contour lines to surround the area are converted into a Bezier curve. The curved surface is expressed by being interpolated by the Gregory curved surface from a cubic Bezier curve. For curved shape to be smoothly connected, the shape of the Bezier curve is corrected so that smooth connection is enabled by the Gregory curved surface among plural groups of curved surfaces to be generated. As a result, a smooth curved surface is generated for a smooth area.