Three-dimensional shape data processing apparatus

摘要

When the user inputs at least four points that designates the path on the surface of a three-dimensional shape represented by three-dimensional shape data, groups of three points in which two points are commonly included in two groups are formed from the input points. Each group of three points defines a plane including the three points. The line of intersection of each plane and the surface of the three-dimensional shape is obtained to calculate lengths of the line of intersection between the adjacent two points of the three points in each of the groups. Two lengths between the two points that are commonly included in two groups along two different lines of intersection are obtained for one length of the path between the two points. As a result, the average of the two lengths is estimated as the length of the path between the two points. The total length of the path is obtained according to the estimated lengths and lengths along lines of intersection.