@article{ma_blendshape_2012,
	title = {A blendshape model that incorporates physical interaction},
	volume = {23},
	url = {http://ict.usc.edu/pubs/A%20blendshape%20model%20that%20incorporates%20physical%20interaction-2.pdf},
	doi = {10.1002/cav.1441},
	abstract = {The linear blendshape technique has been intensively used for computer animation and games because of its simplicity and effectiveness. However, it cannot describe rotational deformations and deformations because of self collision or scene interaction. In this paper, we present a new technique to address these two major limitations by introducing physical-based simulation to blendshapes. The proposed technique begins by constructing a mass–spring system for each blendshape target. Each system is initialized in its steady state by setting the rest length of each spring as the edge length of the corresponding target. To begin shape interpolation, we linearly interpolate the rest lengths of the springs according to a given interpolation factor α ∈ [0,1]. The interpolated shape is then generated by computing the equilibrium of the mass–spring system with the interpolated rest lengths. Results from our technique show physically plausible deformations even in the case of large rotations between blendshape targets. In addition, the new blendshape model is able to interact with other scene elements by introducing collision detection and handling to the mass–spring system.},
	number = {3-4},
	journal = {Computer Animation and Virtual Worlds},
	author = {Ma, Wan-Chun and Wang, Yi-Hua and Fyffe, Graham and Chen, Bing-Yu and Debevec, Paul},
	month = may,
	year = {2012},
	keywords = {Graphics},
	pages = {235--243}
}