simtk.org

Hi everyone,

I want to use opensim for inverse dynamic analysis. I have some trc file from commercial motion capture software. And I got very good result for model scale as well as inverse kinematics. I don't have force data. So I just create some fake ground reaction force data but following the correct format. Then, I followed the steps in the example inverse dynamic analysis: Leg6of9Musc. But opensim always crashes when I click run after setting up everything, there is runtime error:


Thanks,

Chunxia

Hi,

Inverse Dynamics do not use motion capture data or trc files, these are used only for scaling and IK. If IK is working properly then the issue you're running into is unrelated to using marker data. Force data are very important in InverseDynamics. I understand that you made up a file but I'm not sure if/how these forces are applied to the model. If you can provide the model and setup/data files that would be great. You might find it useful to look for a file hs_* created by the Java Virtual Machine when it crashes due to an exception that's not handled, it would contain the stack trace that caused the crash. Even if it's something wrong with the files/model it would be great if you can provide the files so that we can make the code more robust and report meaningful errors rather than crashing.

Best regards,
-Ayman

Hi Ayman,

Thank you for your reply.

In the sample file: Leg6of9Musc.

In this example, after the IK process, they then synchronize the ik trile (motion data) and the force data, and then set up something such as motion setting and external loads, kinematics for external loads, create and edit external force. and then execute inverse dynamics.

I actually modified their force data, so that the time stamp is synchronized with my motion data. Then I just followed exactly the same process. but it keeps crushing...



Chunxia

Hi Ayman,

Can I just send my model, motion file and fake force file to you?


Chunxia

Hi,

I came across another crash when setting up the external loads. Never experience this crash before.

Chunxia