Hi Pouya, Once you have a motion loaded in OpenSim, such as an inverse kinematics result, you may plot muscle-related variables (such as moment arms) against the motion, rather than against a specific joint angle. In the Plotter, for the X-Quantity, select your motion (it will be near the bottom of ...

Last month, I asked about obtaining whole-body center of mass kinematics. This is in the context of running a forward simulation to evaluate the objective function for an optimization problem. I have one case where I only need to know the CM kinematics at the initial time and the final time. Ajay’s ...

Ajay and James,

Thanks so much for the responses. I will give this a try and let you know if I encounter any problems.

Best,
Brian

Hi All, Using the Matlab interface to the API, it is possible to obtain the current velocity (or position) of the center of mass of any segment in a model during a simulation using code such as this: massCenter = Vec3(0.0,0.0,0.0); velocity = Vec3(0.0,0.0,0.0); bodySet = osimModel.getBodySet(); body...

Hi Alex, Thanks for the suggestion. I wasn't planning on recompiling OpenSim from source, but that would certainly do the trick! In the meantime, I think that I've worked out how to run the forward simulations from within Matlab using a simulation Manager, which achieves the desired result without a...

Hi Sherm,

Thanks for the helpful information!

Brian

Hi Sherm, Thanks for the suggestion. I randomly tried a couple of the different Matlab integrators, but I will do a more systematic study of the various integrators, as well as the integrator settings. It looks like with the Manager approach I can indicate which simmath integrator to use. Are one or...

A quick update on my question. I am still not sure about changing the verbosity of the Forward Tool, but based on some further digging, there appear to be at least two other ways to run forward simulations programmatically from within Matlab. I was able to do this for my problem using the native Mat...

Hi All, I am working on an optimization study making use of the Matlab interface to the API. When my script loads the model and initializes it, there is some information written to the screen (truncated for brevity): -------------------------------------------------- Loaded model Arm26_Optimize.osim...

Hi Andy, You should find the recommended mass changes in the Messages window in the GUI (not in the output files). I just ran RRA on a model and this is what was in the Messages window. Hope this helps, Brian ************************************************************ * Summary of Mass Adjustments ...