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OpenSim IK paper

Posted: Tue Sep 07, 2021 2:01 pm
by vigneshrk
Hello,

Would it be possible to determine which paper or algorithm does the OpenSim IK derieve from? For example Visual3d IK is derieved from Van Den Bogert and Su (2008) method.

Also does the generalised coordinates refer to the model coordinate system?

Thanks, and Regards
Vignesh

Re: OpenSim IK paper

Posted: Tue Sep 14, 2021 4:09 pm
by ongcf
A description of the algorithm can be found in the header file (https://github.com/opensim-org/opensim- ... csSolver.h) or corresponding doxygen documentation (https://simtk.org/api_docs/opensim/api_ ... ml#details). The Confluence documentation also has a page too (https://simtk-confluence.stanford.edu/d ... tics+Works).

I think the paper usually cited for this is the 2007 OpenSim paper (https://nmbl.stanford.edu/publications/pdf/Delp2007.pdf), which may cite other papers that could be useful.

Generalized coordinates often align with the model coordinate system, but not always. In some contexts, you have to be careful with this, for instance, with the BallJoint, which use quaternions (https://simtk.org/api_docs/opensim/api_ ... ml#details)