Would like model output and inverse kinematics output in degrees

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Eric Rapp
Posts: 10
Joined: Fri Aug 31, 2018 2:58 pm

Would like model output and inverse kinematics output in degrees

Post by Eric Rapp » Thu Jan 31, 2019 11:47 am

Hello,

I am currently working with two different models (Rajagopal and Arnold) and I noticed that in the coordinates window for the model, the Rajagopal model displays all joint angles in degrees while the Arnold model displays most joint angles in radians (images attached below). This also translates to the results of inverse kinematics analysis where the Rajagopal outputs a motion file with angles in degrees and Arnold in radians.

Is there a way to adjust the Arnold model (in the .osim file) to also output in all joint angles in degrees like the Rajagopal model?
Attachments
Rajagopal_Coordinates.PNG
Rajagopal_Coordinates.PNG (12.01 KiB) Viewed 352 times
Arnold_Coordinates.PNG
Arnold_Coordinates.PNG (11.08 KiB) Viewed 352 times

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Dimitar Stanev
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Joined: Fri Jan 31, 2014 5:14 am

Re: Would like model output and inverse kinematics output in degrees

Post by Dimitar Stanev » Thu Jan 31, 2019 1:04 pm

If you open the .osim file you can find the min and max permissible values for each coordinate in radiance. The GUI transforms these values to degrees automatically.

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Eric Rapp
Posts: 10
Joined: Fri Aug 31, 2018 2:58 pm

Re: Would like model output and inverse kinematics output in degrees

Post by Eric Rapp » Thu Jan 31, 2019 1:26 pm

I see those values in the .osim file and they are the same for both models, but for some reason the Rajagopal displays and outputs in degrees, whereas the Arnold displays and outputs in radians. I would like it to be consistent so I can compare the results from my analysis. Is there a way to do that?

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Ayman Habib
Posts: 2248
Joined: Fri Apr 01, 2005 12:24 pm

Re: Would like model output and inverse kinematics output in degrees

Post by Ayman Habib » Thu Jan 31, 2019 11:28 pm

Hello,

In OpenSim versions before 4.0, users were allowed to specify if a coordinate is Rotational (GUI converts it to degrees for convenience) or Translational or Coupled (never converted).
In version 4.0 that motionType is not exposed and it lives with the joint itself. Check upgrade notes section on how to upgrade model files
https://simtk-confluence.stanford.edu/d ... penSim+4.0

Hope this helps,
-Ayman

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