The Research Of The Key Technologies Of The Geometrical Modeling Oriented To Virtual Sculpture

Virtual sculpture is to use computer technology to realize the sculpture of3D modeling in virtualreality environment. It was combined with the advantage of computer aided design and carving design,and has broad application prospects in industrial design, art design and computer animation.Thesis mainly study on the key technology of geometric modeling technology about virtualsculpture. Based on the research of geometric modeling technology and3D graphic simulation model,Thesis first put forward the virtual sculpture geometric modeling which based on the extended octreemodel. The specific content of the paper mainly include the following aspects:(1) This paper uses BRep presentation method to modeling the cutter, meanwhile, in order toenrich the cutters and realize variety of sculpture forms, we adopt an general cutter model, and we canget any cutters we need through defining the relevant parameter.(2) With the basis and features of traditional octree model, we introduced extended octree modeland its corresponding special data structures. And realize the conversion from BRep or CSG model toextended octree model. And we use improvement processing method for some special geometricalelement in model conversion, so as to improve the conversion precision.(3) This paper adopt the sculpture algorithm which based on the extended octree, and realize thesculpture operation between the BRep model of the cutter swept volume and the extended model ofthe blank. And we first put forward the concept of temporary nodes during the process ofimplementation of the sculpture algorithm. This simplified the sculpture operations between theextended nodes of blank and the swept volume of cutter and increase the calculation speed.(4) According to the characteristics of virtual sculpture, this paper put forward the method ofsimply and substep manage, so that to improve the speed of Sculpture operation while accord withthe required precision, it also improve the continuity of operation and the real-time of show.(5) Rending the graphics with OpenGL according the data after each sculpting, consequently, thispaper carrying out the algorithm of refreshing partly to revise part octree nodes so as to raise theefficiency combining the technology of double buffering and display list in OpenGL, ensuringcontinuity and integrality of each frame.