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How to plot the effects of manual changes in the Opensim models

Posted: Fri Jun 24, 2016 2:53 pm
by arpitbhugul
Hello friends,

I have been working with Opensim for past one month now. I am trying to plot the results of the changes, I make in the opensim Gait model. eg: I would shut off the motion of Joint motion of left leg(in coordinates), so that the model is hopping instead of running. I was expecting to see a change in the ground reaction force pattern. But it remained the same. Can you please help me with this? What am I doing wrong :?: Is it something to with the CMC thing?

Expecting a reply.. Thanking in Advanc..

Arpit Bhugul
M.S. Bioengineering
University of Texas at Arlington

Re: How to plot the effects of manual changes in the Opensim models

Posted: Fri Jun 24, 2016 6:39 pm
by mitkof6
Hi,

How did you estimate the ground reaction forces(grf)? Because CMC expects motion and grf and computes muscle patterns in an inverse manner (measurements->estimation). If you had to estimate a different grf pattern you should do a forward dynamics simulation instead.

Best

Re: How to plot the effects of manual changes in the Opensim models

Posted: Sun Jun 26, 2016 5:20 pm
by arpitbhugul
Hi Jim,

I converted the 'Visual 3d C3D' file to .osim file. The c3d file used GRF and EMG data. I tried doing my operations on this new .osim file.

Also, Is there a good place to learn about the working of this software? I have learnt this software all myself so far. I am trying hard to come up with some good research statement using OpenSim and Visual 3D. Its demoralizing me now. lol.

Best,
Arpit

Re: How to plot the effects of manual changes in the Opensim models

Posted: Sun Jun 26, 2016 7:42 pm
by mitkof6
Also, Is there a good place to learn about the working of this software?
It is hard in the beginning, because there are a lot of things to learn, but you can start here:
http://simtk-confluence.stanford.edu:80 ... %27s+Guide
I am trying hard to come up with some good research statement using OpenSim and Visual 3D.
You don't have to start from scratch, maybe you can find some relative projects (like btk), and do some improvements.

https://github.com/Biomechanical-ToolKit/BTKCore

Re: How to plot the effects of manual changes in the Opensim models

Posted: Sun Jun 26, 2016 9:21 pm
by arpitbhugul
Thank you for the response Jim. I am a mechanical engineer, so btk or other coding projects are difficult right now. But, I really appreciate the user guide link. I will try to soak in as much of it as possible.
I like this forum and understand its importance, given that the resources for this platform are so scarce. Thank you Jim for being so altruistic here.