Characters, like other articulated objects and structures, are typically simulated using articulated dynamics algorithms. There are efficient linear-time algorithms for the simulation of open-chain articulated bodies, but complexity grows notably under additional constraints such as joint limits, loops or contact, or if the bodies undergo stiff joint forces. This paper presents a linear-time algorithm for the simulation of open-chain articulated bodies with joint limits and stiff joint forces. This novel algorithm uses implicit integration to simulate stiff forces in a stable manner, and avoids drift by formulating joint constraints implicitly. One additional interesting feature of the algorithm is that its practical implementation entails only small modi?cations to a popular algorithm.

@InProceedings\{HGCO11,
  author       = "Hernandez, Fernando and Garre, Carlos and Casillas, Rubén and Otaduy, Miguel A.",
  title        = "Linear-Time Dynamics of Characters with Stiff Joints",
  booktitle    = "V Ibero-American Symposium on Computer Graphics (SIACG 2011)",
  month        = "June",
  year         = "2011",
  publisher    = "The Eurographics Association and Blackwell Publishing Ltd",
  organization = "The Eurographics Association",
  url          = "http://gmrv.es/Publications/2011/HGCO11"
}