Graphical Models 64, 61–77 (2002) doi:10.1006/gmod.2002.0570 Sharp Features on Multiresolution Subdivision Surfaces Henning Biermann Media Research Lab, New York University, 719 Broadway, New York, NY 10003 E-mail: biermann@mrl.nyu.edu Ioana M. Martin IBM T. J. Watson Research Center, Hawthorne, NY 10532 E-mail: ioana@us.ibm.com Denis Zorin Media Research Lab, New York University, 719 Broadway, New York, NY 10003 E-mail: dzorin@mrl.nyu.edu and Fausto Bernardini IBM T. J. Watson Research Center, Hawthorne, NY 10532 E-mail: fausto@us.ibm.com Received October 18, 2001; revised January 28, 2002; accepted June 28, 2002 In this paper we describe a method for creating sharp features and trim regions on multiresolution subdivision surfaces along a set of user-defined curves. Operations such as engraving, embossing, and trimming are important in many surface modeling applications. Their implementation, however, is nontrivial due to computational, topological, and smoothness constraints that the underlying surface has to satisfy. The novelty of our work lies in the ability to create sharp features anywhere on a surface and in the fact that the resulting representation remains within the multiresolution subdivision framework. Preserving the original representation has the advantage that other operations applicable to multiresolution subdivision surfaces can subsequently be applied to the edited model. We also introduce an extended set of subdivision rules for Catmull–Clark surfaces that allows the creation of creases along diagonals of control mesh faces. c  2002 Elsevier Science (USA) Key Words: subdivision surfaces; multiresolution; surface editing; sharp features; trimming. 61 1524-0703/02 $35.00 c  2002 Elsevier Science (USA) All rights reserved.