Interactive graphic input system

摘要

In the conventional CAD or CAM system, when a shape must be defined, it should use mathematical models which are formed by B-Reps or CSG method. B-Reps method is more complicated than CSG in data structure and in processing. This invention attempts to utilize merits of the CSG method, express component elements of a three-dimensional solid model in a hierarchical structure so that an element of a a higher order can relocate another element of a lower order on its coordinate system, and an interactive operation can be employed in defining. This method allows an operator to ascertain the progress of the works with his/her own eyes to greatly simplify the works of shape defining of solid models.