Three-Dimensional Data Input by Selection of Hierarchically Defined Blocks

Abstract

This paper discusses inputing 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. The advantages of using this octree design method are: 1. the designer always has a valid three dimensional object, 2. few selections are required for generating a rough design, and 3. each displayed candidate cube serves as a menu for guiding the designer in making decisions. A technique for displaying objects and experimental designs is illustrated.