Harmonic skeleton for realistic character animation

ABSTRACT

Current approaches to skeleton generation are based on topological and geometrical information only; this can be insufficient for realistic character animation, since the location of the joints does not usually match the real bone structure of the model. This paper proposes the use of anatomical information to enhance the skeleton. Using a harmonic function, this information can be recovered from the skeleton itself, which is guaranteed not to have undesired endpoints. The skeleton is computed as a Reeb graph of such a function over the surface of the model. Starting from one point selected on the head of the character, the entire process is fast, automatic and robust; it generates skeletons whose joints can be associated with the character's anatomy. Results are provided, including a quantitative validation of the generated skeletons.

REFERENCES

• 1: Jules Bloomenthal , Chek Lim, Skeletal Methods of Shape Manipulation, Proceedings of the International Conference on Shape Modeling and Applications, p.44, March 01-04, 1999
• 2: {Blu67} Blum H.: A transformation for extracting new descriptors of shape. In Symposium on Models for the Perception of Speech and Visual Form (1967), pp. 362--380.
• 3: {Cal75} Calderon W.: Animal Painting and Anatomy. Dover, 1975.
• 4: Kree Cole-McLaughlin , Herbert Edelsbrunner , John Harer , Vijay Natarajan , Valerio Pascucci, Loops in reeb graphs of 2-manifolds, Proceedings of the nineteenth annual symposium on Computational geometry, June 08-10, 2003, San Diego, California, USA [doi>10.1145/777792.777844]
• 5: {CSYB05} Cornea N., Silver D., Yuan X., Balasubra-Manian R.: Computing hierarchical curve-skeletons of 3d objects. The Visual Computer 21, 11 (2005), 945--955.
• 6: Hubert de Fraysseix, An Heuristic for Graph Symmetry Detection, Proceedings of the 7th International Symposium on Graph Drawing, p.276-285, September 01, 1999
• 7: James W. Demmel , Stanley C. Eisenstat , John R. Gilbert , Xiaoye S. Li , Joseph W. H. Liu, A Supernodal Approach to Sparse Partial Pivoting, SIAM Journal on Matrix Analysis and Applications, v.20 n.3, p.720-755, July 1999 [doi>10.1137/S0895479895291765]
• 8: S. Dong , S. Kircher , M. Garland, Harmonic functions for quadrilateral remeshing of arbitrary manifolds, Computer Aided Geometric Design, v.22 n.5, p.392-423, July 2005 [doi>10.1016/j.cagd.2005.04.004]
• 9: Tamal K. Dey , Jian Sun, Defining and computing curve-skeletons with medial geodesic function, Proceedings of the fourth Eurographics symposium on Geometry processing, June 26-28, 2006, Cagliari, Sardinia, Italy
• 10: {FK97} Fomenko A., Kunii T.: Topological Modeling for Visualization. Springer-Verlag, 1997.
• 11: Nikhil Gagvani , Deborah Silver, Animating volumetric models, Graphical Models, v.63 n.6, p.443-458, November 2001 [doi>10.1006/gmod.2001.0557]
• 12: Masaki Hilaga , Yoshihisa Shinagawa , Taku Kohmura , Tosiyasu L. Kunii, Topology matching for fully automatic similarity estimation of 3D shapes, Proceedings of the 28th annual conference on Computer graphics and interactive techniques, p.203-212, August 2001 [doi>10.1145/383259.383282]
• 13: Sagi Katz , Ayellet Tal, Hierarchical mesh decomposition using fuzzy clustering and cuts, ACM SIGGRAPH 2003 Papers, July 27-31, 2003, San Diego, California
• 14: Jyh-Ming Lien , John Keyser , Nancy M. Amato, Simultaneous shape decomposition and skeletonization, Proceedings of the 2006 ACM symposium on Solid and physical modeling, June 06-08, 2006, Cardiff, Wales, United Kingdom [doi>10.1145/1128888.1128919]
• 15: Francis Lazarus , Anne Verroust, Level set diagrams of polyhedral objects, Proceedings of the fifth ACM symposium on Solid modeling and applications, p.130-140, June 08-11, 1999, Ann Arbor, Michigan, United States [doi>10.1145/304012.304025]
• 16: Pin-Chou Liu , Fu-Che Wu , Wan-Chun Ma , Rung-Huei Liang , Ming Ouhyoung, Automatic Animation Skeleton Construction Using Repulsive Force Field, Proceedings of the 11th Pacific Conference on Computer Graphics and Applications, p.409, October 08-10, 2003
• 17: Xinlai Ni , Michael Garland , John C. Hart, Fair morse functions for extracting the topological structure of a surface mesh, ACM SIGGRAPH 2004 Papers, August 08-12, 2004, Los Angeles, California
• 18: {Ree46} Reeb G.: Sur les points singuliers d'une forme de pfaff complètement intègrable ou d'une fonction numérique. Comptes-Rendus de l'Académie des Sciences 222 (1946), 847--849.
• 19: Lionel Reveret , Laurent Favreau , Christine Depraz , Marie-Paule Cani, Morphable model of quadrupeds skeletons for animating 3D animals, Proceedings of the 2005 ACM SIGGRAPH/Eurographics symposium on Computer animation, July 29-31, 2005, Los Angeles, California [doi>10.1145/1073368.1073386]
• 20: D. Steiner , A. Fischer, Topology Recognition of 3D Closed Freeform Objects Based on Topological Graphs, Proceedings of the 9th Pacific Conference on Computer Graphics and Applications, p.82, October 16-18, 2001
• 21: Yoshihisa Shinagawa , Tosiyasu L. Kunii , Yannick L. Kergosien, Surface Coding Based on Morse Theory, IEEE Computer Graphics and Applications, v.11 n.5, p.66-78, September 1991 [doi>10.1109/38.90568]
• 22: Patricio Simari , Evangelos Kalogerakis , Karan Singh, Folding meshes: hierarchical mesh segmentation based on planar symmetry, Proceedings of the fourth Eurographics symposium on Geometry processing, June 26-28, 2006, Cagliari, Sardinia, Italy
• 23: {TVD06} Tierny J., Vandeborre J., Daoudi M.: 3d mesh skeleton extraction using topological and geometrical analyses. In Pacific Graphics (2006), pp. 409--413.
• 24: {WP02} Wade L., Parent R.: Automated generation of control skeletons for use in animation. The Visual Computer 18 (2002).
• 25: Eugene Zhang , Konstantin Mischaikow , Greg Turk, Feature-based surface parameterization and texture mapping, ACM Transactions on Graphics (TOG), v.24 n.1, p.1-27, January 2005 [doi>10.1145/1037957.1037958]

INDEX TERMS

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