Featherstone's algorithm is a technique used for computing the effects of forces applied to a structure of joints and links (an "open
kinematic chain
In mechanical engineering, a kinematic chain is an assembly of rigid bodies connected by joints to provide constrained (or desired) motion that is the mathematical model for a mechanical system. Reuleaux, F., 187''The Kinematics of Machinery, ...
") such as a
skeleton
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...
used in
ragdoll physics
Ragdoll physics is a type of procedural animation used by physics engines, which is often used as a replacement for traditional static death animations in video games and animated films. As computers increased in power, it became possible to do ...
.
The Featherstone's algorithm uses a reduced coordinate representation. This is in contrast to the more popular
Lagrange multiplier method
In mathematical optimization, the method of Lagrange multipliers is a strategy for finding the local maxima and minima of a function subject to equality constraints (i.e., subject to the condition that one or more equations have to be satisfied e ...
, which uses maximal coordinates.
Brian Mirtich's PhD Thesishas a very clear and detailed description of the algorithm. Baraff's pape
has a discussion and comparison of both
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
s.
References
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External links
Featherstone Multibody in Bullet Physics engineFeatherstone's algorithm implementation in the Moby rigid body dynamics simulatorSource code for implementation of Featherstone's algorithmDescription and referencesMirtich's ThesisRoy Featherstone's home page
Mechanics
Computational physics
Computer physics engines
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