Computer Aided Design Technology for Convex Faceted Gem Cuts Based on the Half-Edge Data Structure

TH166; Aiming to increase the efficiency of gem design and manufacturing,a new method in computer-aided-design (CAD) of convex faceted gem cuts (CFGC) based on Half-edge data structure (HDS),including the algorithms for the implementation is presented in this work.By using objectoriented methods,geometrical elements of CFGC are classified and responding geometrical feature classes are established.Each class is implemented and embedded based on the gem process.Matrix arithmetic and analytical geometry are used to derive the affine transformation and the cutting algorithm.Based on the demand for a diversity of gem cuts,CAD functions both for free-style faceted cuts and parametric designs of typical cuts and visualization and human-computer interactions of the CAD system including two-dimensional and three-dimensional interactions have been realized which enhances the flexibility and universality of the CAD system.Furthermore,data in this CAD system can also be used directly by the gem CAM module,which will promote the gem CAD/CAM integration.