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 proceedingChapter in a published conference proceeding

582 Downloads (Pure)


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 languageEnglish
Title of host publicationSCA '13 Proceedings of the 12th ACM SIGGRAPH/Eurographics Symposium on Computer Animation
Place of PublicationNew York
PublisherAssociation for Computing Machinery
Number of pages6
ISBN (Print)9781450321327
Publication statusPublished - 2013
EventSymposium on Computer Animation 2013 - Anaheim, California, USA United States
Duration: 19 Jul 2013 → …


ConferenceSymposium on Computer Animation 2013
Country/TerritoryUSA United States
CityAnaheim, California
Period19/07/13 → …


  • rods
  • ragdolls
  • games
  • rigid bodies


Dive into the research topics of 'Rod constraints for simplified ragdolls'. Together they form a unique fingerprint.

Cite this