| 摘要 |
PURPOSE:To efficiently generate a complete visible face table by executing the generation processing of a visible face table based on information holding the visible face table. CONSTITUTION:The opposite face list generation part 4 of a processor 2 reads face normal information out of a memory device 1 and generates a list showing faces (opposite faces) having the reverse face normals of the normal stated by said information. A visible face list generation part 5 sets all combinations of lists composed of 1-(N-1) number of faces among N-number of faces, excludes the combinations including a pair of the face and its opposite one, and generates a provisional visible face list in the combination with others than excluded pairs. With respect to the provisional visible face list, a visible area deciding part 6 inspects whether or not all the visible faces on one list have a common visible space. If so, the visible face list is outputted to a memory device 3. |
