Tomohiko Mukai
Shigeru Kuriyama
Abstract
Dynamic skin deformation is vital for creating life-like characters, and its real-time computation is in great demand in interactive applications. We propose a practical method to synthesize plausible and dynamic skin deformation based on a helper bone rig. This method builds helper bone controllers for the deformations caused not only by skeleton poses but also secondary dynamics effects. We introduce a state-space model for a discrete time linear time-invariant system that efficiently maps the skeleton motion to the dynamic movement of the helper bones. Optimal transfer of nonlinear, complicated deformations, including the effect of soft-tissue dynamics, is obtained by learning the training sequence consisting of skeleton motions and corresponding skin deformations. Our approximation method for a dynamics model is highly accurate and efficient owing to its low-rank property obtained by a sparsity-oriented nuclear norm optimization. The resulting linear model is simple enough to easily implement in the existing workflows and graphics pipelines. We demonstrate the superior performance of our method compared to conventional dynamic skinning in terms of computational efficiency including LOD controls, stability in interactive controls, and flexible expression in deformations.
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- Andersen, M. S., Dahl, J., and Vandenberghe, L. CVXOPT: A python package for convex optimization. http://cvxopt.org.Google Scholar
- Angelidis, A., and Singh, K. 2007. Kinodynamic skinning using volume-preserving deformations. In Proceedings of ACM SIGGRAPH/Eurographics Symposium on Computer Animation 2007, 129--140. Google ScholarDigital Library
- de Aguiar, E., Sigal, L., Treuille, A., and Hodgins, J. K. 2010. Stable spaces for real-time clothing. ACM Transactions on Graphics 29, 4, 106:1--106:9. Google ScholarDigital Library
- Fan, Y., Litven, J., and Pai, D. K. 2014. Active volumetric musculoskeletal systems. ACM Transactions on Graphics 33, 4, 152:1--152:9. Google ScholarDigital Library
- Hahn, F., Martin, S., Thomaszewski, B., Sumner, R., Coros, S., and Gross, M. 2012. Rig-space physics. ACM Transactions on Graphics 31, 4, 72:1--72:8. Google ScholarDigital Library
- Hahn, F., Thomaszewski, B., Coros, S., Sumner, R., and Markus. 2013. Efficient simulation of secondary motion in rig-space. In Proceedings of ACM SIGGRAPH/Eurographics Symposium on Computer Animation 2013, 165--171. Google ScholarDigital Library
- Hsu, E., Pulli, K., and Popović, J. 2005. Style translation for human motion. ACM Transactions on Graphics 24, 3, 1082--1089. Google ScholarDigital Library
- James, D. L., and Pai, D. K. 2002. Dyrt: Dynamic response textures for real time deformation simulation with graphics hardware. ACM Transactions on Graphics 21, 3, 582--585. Google ScholarDigital Library
- Kavan, L., and Sorkine, O. 2012. Elasticity-inspired deformers for character articulation. ACM Transactions on Graphics 31, 6, 196:1--196:8. Google ScholarDigital Library
- Kavan, L., Collins, S., Zara, J., and O'Sullivan, C. 2007. Skinning with dual quaternions. In Proceedings of ACM SIGGRAPH Symposium on Interactive 3D Graphics 2007, 39--46. Google ScholarDigital Library
- Kim, J., and Kim, C.-H. 2011. Implementation and application of the real-time helper-joint system. In Game Developers Conference 2011.Google Scholar
- Kry, P. G., James, D. L., and Pai, D. K. 2002. Eigenskin: Real time large deformation character skinning in hardware. In Proc. of ACM SIGGRAPH/Eurographics Symposium on Computer Animation 2002, 153--159. Google ScholarDigital Library
- Larimore, W. 1990. Canonical variate analysis in identification, filtering and adaptive control. In Proceedings of Control & Decision Conference, 596--604.Google ScholarCross Ref
- Le, B. H., and Deng, Z. 2012. Smooth skinning decomposition with rigid bones. ACM Transactions on Graphics 31, 6, 199:1--199:10. Google ScholarDigital Library
- Le, B. H., and Deng, Z. 2014. Robust and accurate skeletal rigging from mesh sequences. ACM Transactions on Graphics 33, 4, 84. Google ScholarDigital Library
- Lewis, J. P., Cordner, M., and Fong, N. 2000. Pose space deformation: A unified approach to shape interpolation and skeleton-driven deformation. In Proceedings of SIGGRAPH 2000, 165--172. Google ScholarDigital Library
- Li, D., Sueda, S., Neog, D. R., and Pai, D. K. 2013. Thin skin elastodynamics. ACM Transactions on Graphics 32, 4, 49:1--49:9. Google ScholarDigital Library
- Liu, Z., and Vandenberghe, L. 2009. Interior-point method for nuclear norm approximation with application to system identification. SIAM Journal on Matrix Analysis and Application 31, 3, 1235--1256.Google ScholarDigital Library
- Liu, Z., Hansson, A., and Vandenberghe, L. 2013. Nuclear norm system identification with missing inputs and outputs. Systems & Control Letters 62, 8, 605--612.Google ScholarCross Ref
- Liu, Z. 2009. Structured Semidefinite Programs in System Identification and Control. PhD thesis, University of California, Los Angeles.Google Scholar
- Ljung, L. 1999. System Identification: Theory for the User. Prentice Hall. Google ScholarDigital Library
- Loper, M., and Black, N. M. M. J. 2014. Motion and shape capture from sparse markers. ACM Transactions on Graphics 33, 6, 220:1--220:13. Google ScholarDigital Library
- Loper, M., Mahmood, N., Romero, J., Pons-Moll, G., and Black, M. J. 2015. SMPL: A skinned multi-person linear model. ACM Transactions on Graphics 34, 6, 248:1--248:16. Google ScholarDigital Library
- Magnenat-Thalmann, N., Laperrière, R., and Thalmann, D. 1988. Joint-dependent local deformations for hand animation and object grasping. In Proceedings on Graphics Interface '88, 26--33. Google ScholarDigital Library
- Mari, J., Stoica, P., and McKelvey, T. 2000. Vector ARMA estimation: a reliable subspace approach. IEEE Transaction on Signal Processing 48, 7, 2092--2104. Google ScholarDigital Library
- Mohr, A., and Gleicher, M. 2003. Building efficient, accurate character skins from examples. ACM Transactions on Graphics 22, 3, 562--568. Google ScholarDigital Library
- Moor, B. D., Marc Moonen and, L. V., and Vandewalle, J. 1988. A geometrical approach for the identification of state space models with singular value decomposition. In International Conference on Acoustics, Speech, and Signal Processing, vol. 4, 2244--2247.Google Scholar
- Mukai, T. 2015. Building helper bone rigs from examples. In Proceedings of ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games 2015, 77--84. Google ScholarDigital Library
- Neumann, T., Varanasi, K., Hasler, N., Wacker, M., Magnor, M., and Theobalt, C. 2013. Capture and statistical modeling of arm-muscle deformations. Computer Graphics Forum 32, 2, 285--294.Google ScholarCross Ref
- Park, S. I., and Hodgins, J. K. 2008. Data-driven modeling of skin and muscle deformation. ACM Transactions on Graphics 27, 3, 96:1--96:6. Google ScholarDigital Library
- Parks, J. 2005. Helper joints: Advanced deformations on runtime characters. In Game Developers Conference 2005.Google Scholar
- Pons-Moll, G., Romero, J., Mahmood, N., and Black, M. J. 2015. Dyna: A model of dynamic human shape in motion. ACM Transactions on Graphics 33, 4, 120:1--120:10. Google ScholarDigital Library
- Recht, B., Fazel, M., and Parrilo, P. A. 2010. Guaranteed minimum-rank solutions of linear matrix equations via nuclear norm minimization. SIAM Review 52, 3, 471--501. Google ScholarDigital Library
- Rumman, N. A., and Fratarcangeli, M. 2015. Position-based skinning for soft articulated characters. Computer Graphics Forum 34, 6, 240--250. Google ScholarDigital Library
- Shi, X., Zhou, K., Tong, Y., Desbrun, M., Bao, H., and Guo, B. 2008. Example-based dynamic skinning in real time. ACM Transactions on Graphics 27, 3, 29:1--29:8. Google ScholarDigital Library
- Tibshirani, R. 2011. Regression shrinkage and selection via the lasso: A retrospective. Journal of the Royal Statistical Society: Series B (Statistical Methodology) 73, 3, 273--282.Google ScholarCross Ref
- Verhaegen, M. 1994. Identification of the deterministic part of MIMO state space models given in innovations form from input-output data. Automatica 30, 1, 61--74. Google ScholarDigital Library
- Viberg, M. 1995. On subspace-based methods for the identification of linear time-invariant systems. Automatica 31, 12, 1835--1852. Google ScholarDigital Library
- Wang, X. C., and Phillips, C. 2002. Multi-weight enveloping: Least-squares approximation techniques for skin animation. In Proceedings of ACM SIGGRAPH/Eurographics Symposium on Computer Animation, 129--138. Google ScholarDigital Library
- Wang, R. Y., Pulli, K., and Popović, J. 2007. Real-time enveloping with rotational regression. ACM Transactions on Graphics 26, 3, 73:1--73:10. Google ScholarDigital Library
- Xia, S., Wang, C., Chai, J., and Hodgins, J. 2015. Realtime style transfer for unlabeled heterogeneous human motion. ACM Transactions on Graphics 34, 4, 119:1--119:10. Google ScholarDigital Library
Index Terms
- Efficient dynamic skinning with low-rank helper bone controllers
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