Thank you for developing the great model ARMS Wrist and Hand Model, which meets our demand on studying the hand, wrist, and forearm movements. I encountered two problems while using the model. I wondered if you have any suggestions.
The first is that most models in the downloaded package have 23 DoFs without supination/pronation, except for the model in Tenodesis Module with a locked supination/pronation. I tried to activate this DoF by 1) setting "<locked>false</locked>" in Tenodesis model or 2) copying the "pro_sup" related codes to the other .osim files. With the revised .osim, the MSK model can move with the pro/sup. To check the validity of the modified model, I exported the muscle lengths during a simple movement (e.g., wrist flexion/extension) by using the GUI and the python API. The muscle lengths exported by these two methods are not the same using the modified model (before revision, they were the same). The amps of fibre lengths exported by GUI are lower than by API. I wondered if this is because I incorrectly revised the .osim file and if you have any advice on how to correctly activate this DoF.
The second question is the scaling of the model. I tried to scale the model to match the MoCap data. Seems that the model cannot be moved to match the MoCap markers because it was fixed to the ground. I found that the thorax was attached to the ground frame. So I removed the attached thorax in ground and made the following changes: adding an object of "thorax" in BodySet (mass and inertia borrowed from another model) and adding "ground_thorax" in JointSet with three rotations and three translations. I wondered whether this is the right way to enable the scaling.
Thank you for your time. Very appreciated if you have any advice!
Best regards,
Shihan