Attribute based interfaces for geometric modeling

Computer Gaming has some unique modeling needs not anticipated with the traditional modeling techniques that evolved in CAD/CAM or animation. Real-time display, economical data base, novice user interaction, collaborative design, cost effective animations and tight polygon count are examples of modeling needs that are desirable in all graphics environments, but they gain added emphasis in gaming. Mathematical and topological specifications, however, often impede the preceding facilities. B-spine surface modeling (NURBS) is the current convention. It requires a rectangular arrangement of surface patches that create large databases and costly evaluations while imposing a heavy burden on the uninitiated designer because they do not always fit the natural configuration indicated by the object. We describe a new design method, FreeDimension, which enables freely designable topologies by incorporating multisided surface patches and curve T-junctions. It fosters design by allowing one to focus on the feature curves of the object, while eliminating curves that only exist due to the underlying mathematics. We also describe the efficiency of FreeDimension in computation and storage, which makes this method attractive for interactive and collaborative applications.