disarticulation of bones after scaling MOBL_ARMS_41

[Kristy Godoy]

Hello,
I'm using OpenSim 4.1.
The model is the MOBL_ARMS_41.osim
I have added some markers to the humerus, forearm and hand. I checked that the new markers were on the correct parent.
I also set the model to 0 in the coordinates related to the thorax (translational and rotational).
I set the trc file from a static file, the trc orientation matches the model orientation.
I'm using the opensim gui as administrator.
I'm a windows user, currently with windows 10.
When I run the scale tool, with and without the preserve mass distribution option checked, the humerus, radius and ulna dissarticulate, I dont get any error in the messages windows, nor in the err.log file.

I attached some pictures to show the issue.

Anyone has a clue what may be happening and how can I solve this?

Thanks for the help!

[Ayman Habib]

Hi Kristy,

This likely is a visualization only problem that we fixed already in later versions of OpenSim. That problem was caused by losing track of the folder where the model came from so instead of the application using the MOBL_ARMS custom geometry folder it's using the stock geometry folder which has similar file names but different meshes. If you save the scaled model in the same folder as the unscaled model and reload it in the application, you should see the correct geometry/meshes. You could also try the latest version 4.5, just be aware that if you save the model in a more recent version you may not be able to go back to using the same model in version 4.1

Hope this helps,
-Ayman

[Kristy Godoy]

Hello Ayman, thanks for the help.
I did what you suggested, I saved the scaled model in the same folder as the unscaled model and reloaded it and it displayed just fine.

I appreciate your quick response!

[Kristy Godoy]

Hello, I didn't know if I should open a new topic or not, I would like to know if the muscle actually changed its origin point or is it a visualization issue?
I applied the IK tool to the scaled model, and at two time instants the LAT1 muscle apparently changes its origin point.
How can I check if it is just a visualization issue?

Thanks for the help!