DEVICE AND METHOD FOR GENERATING HIERARCHIZED POLYGON DATA, AND DEVICE AND METHOD FOR GENERATING THREE-DIMENSIONAL REAL-TIME IMAGE WHILE USING RELEVANT HIERARCHIZED POLYGON DATA

摘要

PROBLEM TO BE SOLVED: To reduce storage area of polygon data when displaying an object by hierarchically determining the apex of a polyhedron having a high degree of approximation to the object rather than a basic polyhedron. SOLUTION: A representative point converting part 1021 virtually cuts an object, obtains a coordinate on the outer periphery of a cross section and defines original polygon data as representative point data. A polygon hierarchizing part 1022 takes a line segment between representative points and forms an outer periphery. A length from an arbitrary start point on the outer periphery to the midpoint of a length around the outer periphery is compared with the length of a line segment from the start point to the midpoint. When the absolute value of a difference between both the length is more than a prescribed value, a point corresponding to the midpoint from the start point to the midpoint is further obtained. The provided start point and midpoint become apex data in the hierarchized polygon data. The first provided start point and midpoint become basic polygon data 1061 and the midpoint provided later becomes detailed polygon data 1062.