An Interactive Solid Modeling Tool

Sculpt, an interactive polyhedral solid modeling system, combines the effectiveness of BSP trees for performing geometric search, set operations, and determination of visibility, with the rendering performance of the AT&T Pixel Machines to provide interactive SCUlpting of texture mapped solids. The paradigm presented to the user is one in which a tool is used to modify a workpiece repeatedly by set operations (union, difference, or intersection). The user may choose between performing one set operation at a time with repositioning of the tool between operations, or sweeping the tool during which either union or difference is performed "continuously" (at sampled tool positions). Solid near-plane clipping is also provided using a BSP tree clipping algorithm. The user interface is simple and was designed to allow portability to a variety of workstations. Update rates using a Sun 3(260 and a Pixel Machine 964 for texture mapped models of -1000 polygons require -0.2 secs per update when using a simple tool.