Deformable object animation using reduced optimal control
- 27 July 2009
- journal article
- research article
- Published by Association for Computing Machinery (ACM) in ACM Transactions on Graphics
- Vol. 28 (3), 1-9
- https://doi.org/10.1145/1531326.1531359
Abstract
Keyframe animation is a common technique to generate animations of deformable characters and other soft bodies. With spline interpolation, however, it can be difficult to achieve secondary motion effects such as plausible dynamics when there are thousands of degrees of freedom to animate. Physical methods can provide more realism with less user effort, but it is challenging to apply them to quickly create specific animations that closely follow prescribed animator goals. We present a fast space-time optimization method to author physically based deformable object simulations that conform to animator-specified keyframes. We demonstrate our method with FEM deformable objects and mass-spring systems. Our method minimizes an objective function that penalizes the sum of keyframe deviations plus the deviation of the trajectory from physics. With existing methods, such minimizations operate in high dimensions, are slow, memory consuming, and prone to local minima. We demonstrate that significant computational speedups and robustness improvements can be achieved if the optimization problem is properly solved in a low-dimensional space. Selecting a low-dimensional space so that the intent of the animator is accommodated, and that at the same time space-time optimization is convergent and fast, is difficult. We present a method that generates a quality low-dimensional space using the given keyframes. It is then possible to find quality solutions to difficult space-time optimization problems robustly and in a manner of minutes.Keywords
Funding Information
- Division of Computing and Communication Foundations (CCF-0810888)
This publication has 31 references indexed in Scilit:
- A survey of spatial deformation from a user-centered perspectiveACM Transactions on Graphics, 2008
- Animating oscillatory motion with overlapACM Transactions on Graphics, 2008
- TRACKSACM Transactions on Graphics, 2007
- Many-worlds browsing for control of multibody dynamicsACM Transactions on Graphics, 2007
- Subspace gradient domain mesh deformationACM Transactions on Graphics, 2006
- Model reduction for real-time fluidsACM Transactions on Graphics, 2006
- Learning physics-based motion style with nonlinear inverse optimizationACM Transactions on Graphics, 2005
- Adaptation of performed ballistic motionACM Transactions on Graphics, 2005
- Interactive skeleton-driven dynamic deformationsACM Transactions on Graphics, 2002
- Dimensional model reduction in non‐linear finite element dynamics of solids and structuresInternational Journal for Numerical Methods in Engineering, 2001