METHOD OF IMAGE PROCESSING, IMAGE PROCESSING APPARATUS, IMAGE PROCESSING PROGRAM AND RECORDING MEDIUM

To enable automatic generation of a cutting curve for a trimming process, for example, even when the line of intersection between two surfaces is a group of lines including a plurality of line segments or curved line segments. A series of processes including a first process to determine whether the line of intersection is a group of lines including a plurality of line segments or curved line segments or a single line segment or curved line segment and a second process to extend at least a line segment or curved line segment out of two adjacent line segments or curved line segments to connect the adjacent line segments or curved line segments with each other when the line of intersection is a group of lines are repeated until the result of the determination in the first process shows that the line of intersection is a single line segment or curved line segment to make the line of intersection into a single line segment or curved line segment.