Spherical blend skinning: a real-time deformation of articulated models

ABSTRACT

Skin deformation based on an underlying skeleton is a common method to animate believable organic models. The most widely used skeletal animation algorithm, linear blend skinning, is also known as skeleton subspace deformation, vertex blending, or enveloping. It runs in real-time even on a low-end hardware but it is also notorious for its failures, such as the collapsing-joints artifacts. We present a new algorithm which removes these shortcomings while maintaining almost the same time and memory complexity as the linear blend skinning. Unlike other approaches, our method works with exactly the same input data as the popular linear version. This minimizes the cost of upgrade from linear to spherical blend skinning in many existing applications: the data structures and models need no change at all. The paper discusses also theoretical properties of rotation interpolation, essential to spherical blend skinning.

REFERENCES

• 1: Marc Alexa, Linear combination of transformations, Proceedings of the 29th annual conference on Computer graphics and interactive techniques, July 23-26, 2002, San Antonio, Texas
• 2: E. Anderson , Z. Bai , C. Bischof , L. S. Blackford , J. Demmel , Jack J. Dongarra , J. Du Croz , S. Hammarling , A. Greenbaum , A. McKenney , D. Sorensen, LAPACK Users' guide (third ed.), Society for Industrial and Applied Mathematics, Philadelphia, PA, 1999
• 3: Jules Bloomenthal, Medial-based vertex deformation, Proceedings of the 2002 ACM SIGGRAPH/Eurographics symposium on Computer animation, July 21-22, 2002, San Antonio, Texas [doi>10.1145/545261.545285]
• 4: Samuel R. Buss , Jay P. Fillmore, Spherical averages and applications to spherical splines and interpolation, ACM Transactions on Graphics (TOG), v.20 n.2, p.95-126, April 2001 [doi>10.1145/502122.502124]
• 5: Eberly, D. 2001. 3D game engine design: a practical approach to real-time computer graphics. Morgan Kaufmann Publishers Inc.
• 6: Kavan, L., and ŽÁra, J. 2003. Real-time skin deformation with bones blending. In WSCG Short Papers Proceedings.
• 7: Paul G. Kry , Doug L. James , Dinesh K. Pai, EigenSkin: real time large deformation character skinning in hardware, Proceedings of the 2002 ACM SIGGRAPH/Eurographics symposium on Computer animation, July 21-22, 2002, San Antonio, Texas [doi>10.1145/545261.545286]
• 8: Lander, J. 1998. Skin them bones: Game programming for the web generation. Game Developer Magazine (May), 11--16.
• 9: Lander, J. 1999. Over my dead, polygonal body. Game Developer Magazine (October), 17--22.
• 10: J. P. Lewis , Matt Cordner , Nickson Fong, Pose space deformation: a unified approach to shape interpolation and skeleton-driven deformation, Proceedings of the 27th annual conference on Computer graphics and interactive techniques, p.165-172, July 2000 [doi>10.1145/344779.344862]
• 11: N. Magnenat-Thalmann , R. Laperrière , D. Thalmann, Joint-dependent local deformations for hand animation and object grasping, Proceedings on Graphics interface '88, p.26-33, December 1989, Edmonton, Alberta, Canada
• 12: Nadia Magnenat Thalmann , Frederic Cordier , Hyewon Seo , George Papagianakis, Modeling of Bodies and Clothes for Virtual Environments, Proceedings of the 2004 International Conference on Cyberworlds (CW'04), p.201-208, November 18-20, 2004 [doi>10.1109/CW.2004.47]
• 13: Alex Mohr , Michael Gleicher, Building efficient, accurate character skins from examples, ACM Transactions on Graphics (TOG), v.22 n.3, July 2003
• 14: Alex Mohr , Luke Tokheim , Michael Gleicher, Direct manipulation of interactive character skins, Proceedings of the 2003 symposium on Interactive 3D graphics, April 27-30, 2003, Monterey, California [doi>10.1145/641480.641488]
• 15: Sang Il Park , Hyun Joon Shin , Sung Yong Shin, On-line locomotion generation based on motion blending, Proceedings of the 2002 ACM SIGGRAPH/Eurographics symposium on Computer animation, July 21-22, 2002, San Antonio, Texas [doi>10.1145/545261.545279]
• 16: Ken Shoemake, Animating rotation with quaternion curves, Proceedings of the 12th annual conference on Computer graphics and interactive techniques, p.245-254, July 1985
• 17: Peter-Pike J. Sloan , Charles F. Rose, III , Michael F. Cohen, Shape by example, Proceedings of the 2001 symposium on Interactive 3D graphics, p.135-143, March 2001 [doi>10.1145/364338.364382]
• 18: Paul Steed, Animating Real-Time Game Characters with Cdrom, Charles River Media, Inc., Rockland, MA, 2002
• 19: Xiaohuan Corina Wang , Cary Phillips, Multi-weight enveloping: least-squares approximation techniques for skin animation, Proceedings of the 2002 ACM SIGGRAPH/Eurographics symposium on Computer animation, July 21-22, 2002, San Antonio, Texas [doi>10.1145/545261.545283]
• 20: Weber, J. 2000. Run-time skin deformation. In Proceedings of Game Developers Conference.

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.7 Three-Dimensional Graphics and Realism
          Subjects: Animation

Keywords:
deformation, skeletal animation, skinning