GEOMETRIC REFINEMENT ALGORITHMS IN COLLISION-BASEDELECTRIC SCULPTING

摘要

Complex free-form 3D objects can be created either byrndigitizing a real world object, or directly on a computerrnusing a CAD tool. Micro operations of the traditional 3Drnsurface modeling tools often require specification andrnmanipulation of individual vertex points, thus extremelyrntedious and sometimes even impractical. Our group hasrndeveloped an interactive, collision-based electronicrnsculpting system for efficient free-form surface modeling,rncalled the e-Sculptor. It operates in a manner emulatingrnthe real world process of clay sculpting. When a rigidrn“tool” is pushed against a piece of plastically deformablern“clay”, the “clay's” shape is changed at the local collisionrnsite. This paper focuses on three geometric refinementrnalgorithms involved in collision detection andrndeformation operations. It provides a systematic handlingrnof a variety of situations encountered in the refinementrnprocess, and produces significantly improved results,rnparticularly at the boundaries of collision regions.