THREE-DIMENSIONAL DATA INPUT BY SELECTION OF HIERARCHICALLY DEFINED BLOCKS.

This paper discusses inputting three dimensional solid object data by means of a two dimensional tablet. This method involves refining an object by gradually generalizing a class of 'permissible' objects. The design of an object is first limited to an octree, which is a set of cubes. At this step, a single selection can create, divide or destroy a cube. It is expected that after this rough design step has been completed, the designer can go on to the next step in which the target object is a polyhedron. A technique for displaying objects and experimental designs is illustrated.