Opening mot files in 4.0

[Katie Werner]

Hi Everyone,

I'm trying to open a .mot file in 4.0, but I can't view the ground reaction data. The .mot file opens without an issue in OpenSim 3.3.

The ground reaction data is represented in the .mot file using the format described here:
https://simtk-confluence.stanford.edu:8 ... na.motFile

I have already scaled the osim file, so I open the scaled model (File -> Open Model), then load the mot file (File -> Load Motion). My scaled osim and mot file can be downloaded here:
https://www.dropbox.com/s/iq20wnbyvor7z ... e.zip?dl=0

I'm not sure if I'm opening the mot file incorrectly - or if it's just an incorrect setting in the 3D viewer. Any help is appreciated!

Thank you!

[Thomas Uchida]

If your model contains CustomJoints with coupled motion, please see the fourth bullet under "Upgrading your model files" on the "Upgrade Notes for OpenSim 4.0" confluence page: https://simtk-confluence.stanford.edu:8 ... penSim+4.0.

[Katie Werner]

Thank you Thomas!

I'm using the gait2392 model. I noted under bullet 4 it says if there's an issue it the GUI will present you with a warning but I'm not receiving a warning. The coordinates appear to be loading correctly since the motion appears as I expect it to. I did note that the model does refer to <motion_type>rotational, so I used Tools -> Convert Files to convert the osim file into version 4 format, but the file ground reaction data still doesn't appear. The gait2392 osim file I've always used doesn't reference the ground_force signals - do they now need to be referenced in the osim file?

My apologies, I'm sure I could be missing something obvious.

Thank you,
-Katie

[Ayman Habib]

Hi Katie,

OpenSim 4.0 uses a more strict convention for motion files that you load (due to strict enforcement of state names etc.), so when you load a motion, only states are applied. To see any additional objects (e.g. markers, or ground reaction forces) you need to use the "associate motion data" function available from the context menu of the node representing the motion in the navigator.
https://simtk-confluence.stanford.edu:8 ... =H31YOZ3BP

Please try that with the provided data files of gait2392 example, and you'll be able to see GRF arrows drawn along with the motion.

Hope this helps,
-Ayman

[Katie Werner]

Hi Aymen,

That was it - thank you so much!

Cheers,
-Katie