中文摘要：

E-mail： bz05@mails.tsinghua.edu.cn, Zhe Bian is a Ph.D. candidate at Department of Computer Science and Technology in Tsinghua University. His research interests include digital geometry processing. He is a student member of China Computer Federation. E-mail： shimin@tsinghua.edu.cn; Shi-Min Hu obtained his Ph.D. degree in 1996 from Zhejiang University. He is currently a chair professor of computer science at Tsinghua University. His research interests include digital geometry processing, video processing, rendering, computer animation, and computeraided geometric design. He is on the editorial board of Computer Aided Design, and he is a senior member of China Computer Federation. E-mail：Ralph.Martin@cs.cardiff.ac.uk, Ralph R. Martin obtained his Ph.D. degree in 1983 from Cambridge University and is now professor at Cardiff University. He has published over 170 papers and 10 books covering such topics as solid and surface modeling, intelligent sketch input, geometric reasoning, reverse engineering, and various aspects of computer graphics. He ison the editorial boards of Computer Aided Design and the International Journal of Shape Modelling.