Hidden line processing method for erasing hidden lines in projecting a three-dimensional model consisting of a plurality of polygons onto a two-dimensional plane

摘要

A hidden line processing method includes the steps of obtaining the maximum value PZ_max of the Z-axis direction component of each vertex in a viewpoint coordinate system for each of the plurality of polygons; sorting the plurality of polygons in a descending order based on the obtained maximum values PZ_max; obtaining a value LZ_min that is the smaller of the Z-axis direction components in the viewpoint coordinate system of two end points of an arbitrary line obtained from the plurality of polygons; and comparing the maximum value PZ_max of the Z-axis direction component of the plurality of polygons with the value LZ_min that is the smaller of the above obtained Z-axis direction components of the arbitrary line, in the sorted order, wherein at the time when LZ_min≧PZ_max, determination of whether or not the lines are hidden lines is avoided for polygons subsequent to the plurality of polygons sorted.