The inverse kinematics solution minimizes a weighted sum of squared errors using IPOPT, a non-linear optimizer.

What algorithm is used for solving the inverse kinematics problem in OpenSim?

<t><br/> As of OpenSim 1.0, the only model modifications available from the GUI are changes to muscles.<br/> <br/> The GUI is not yet in place to let you add degrees of freedom (coordinates) and adjust their properties, or the properties of any other model components other than muscles. <br/> <br/> ...

On the weights tab of the IK tool you can disable whatever markers that you do not want to track.

Force data is imported through the motion file input for IK and is carried over to IK output motion for later usage.

Hope that helps,
-Ayman

What changes can be made to OpenSim models in the GUI? Is it possible to build a model from scratch?

As of version 1.0, OpenSim does not read C3D files directly. Users need to preprocess these files to put their data in the file formats that OpenSim supports:

.mot SIMM motion files
.trc Motion capture files

Does OpenSim 1.0 support importing C3D files directly?

All,

Just testing the convenience of the public forums utility on simtk.org.

-Ayman