Rod constraints for simplified ragdolls

Christopher Lewin; Matt Thorman; Tom Waterson; Chris Williams; Phil Willis

doi:10.1145/2485895.2485896

Rod constraints for simplified ragdolls

Christopher Lewin, Matt Thorman, Tom Waterson, Chris Williams, Phil Willis

Research output: Chapter or section in a book/report/conference proceeding › Chapter in a published conference proceeding

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Abstract

Physics-based animation has become a standard feature in modern
games. Typically, the bones in a character’s animation rig are
each associated with a simulated rigid body, leading to a jointed assembly
commonly called a ragdoll. The high density of animation
bones in the spine area can cause instability and performance issues,
so we are motivated to find a simplified physical representation for
this region.

We approximate the spine region of a ragdoll as an inextensible
elastic curve, building a circular arc constraint based on the Kirchhoff
rod model. Our simplified spine shows improved performance
and stability over the standard group of socket joints, and proves
to be more controllable. To model general elastic rods we use soft
position constraints in place of forces, leading to a stable maximal
coordinate formulation of inextensible Kirchhoff rods.

Original language	English
Title of host publication	SCA '13 Proceedings of the 12th ACM SIGGRAPH/Eurographics Symposium on Computer Animation
Place of Publication	New York
Publisher	Association for Computing Machinery
Pages	79-84
Number of pages	6
ISBN (Print)	9781450321327
DOIs	https://doi.org/10.1145/2485895.2485896
Publication status	Published - 2013
Event	Symposium on Computer Animation 2013 - Anaheim, California, USA United States Duration: 19 Jul 2013 → …

Conference

Conference	Symposium on Computer Animation 2013
Country/Territory	USA United States
City	Anaheim, California
Period	19/07/13 → …

Keywords

rods
ragdolls
games
rigid bodies

Access to Document

10.1145/2485895.2485896

Rod Constraints for Simplified Ragdolls
"The definitive version was published in SCA '13 Proceedings of the 12th ACM SIGGRAPH/Eurographics Symposium on Computer Animation, pages 79-84, 2013, http://doi.acm.org/10.1145/2485895.2485896 Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than the author(s) must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Permissions@acm.org.
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Cite this

Rod constraints for simplified ragdolls. / Lewin, Christopher; Thorman, Matt; Waterson, Tom et al.
SCA '13 Proceedings of the 12th ACM SIGGRAPH/Eurographics Symposium on Computer Animation. New York: Association for Computing Machinery, 2013. p. 79-84.

Research output: Chapter or section in a book/report/conference proceeding › Chapter in a published conference proceeding

Lewin, C, Thorman, M, Waterson, T, Williams, C & Willis, P 2013, Rod constraints for simplified ragdolls. in SCA '13 Proceedings of the 12th ACM SIGGRAPH/Eurographics Symposium on Computer Animation. Association for Computing Machinery, New York, pp. 79-84, Symposium on Computer Animation 2013, Anaheim, California, USA United States, 19/07/13. https://doi.org/10.1145/2485895.2485896

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Rod constraints for simplified ragdolls

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