I encountered a similar issue on Windows yesterday when trying to install the OpenSim (4.4.1) package on a fresh Anaconda environment. Using the old installation method (running setup_win_python.py and pip install) failed on Python 3.8.16. However, I tried it on a Python 3.8.13 environment and it wo...

Oh yes, I remember now I ran into that also. I actually brought that up with the dev team: https://github.com/opensim-org/opensim-core/issues/3154 I started trying to add the stretch stateInfo, and ended up basically recreating MocoTrack in Python so I could insert the stateInfo at the right place i...

Hi Ross, Sorry for the delay, just saw your post. You may have figured this out already, but you'll need to add state info (e.g., max and min) for the "stretch" state of the ClutchedPathSpring. Stretch is the change in length of the spring from it's resting length, so you can set it accordingly. I t...

Hi Ross - thanks for your thoughts. The ClutchedPathSpring components are massless, so that shouldn't be an issue. The default dissipation is 0.3, but I lowered it to 0.01 for this example. You are correct about the dynamics being discontinuous, though there are some nuances. If the control input u ...

I've attached a couple of videos showing the "hop" motion I referred to in my previous post. The files are zipped mp4s.

I'm attempting to use ClutchedPathSpring components to represent an exosuit in a Moco simulation (2D, tracking, half gait cycle with periodicity constraints), and am getting some results I don't fully understand. I've attached a few examples that illustrate the issue I'm seeing. I started by setting...

Hi Evan - I've run into this before also. The extra timesteps are added by the lowpass filter applied to the motion data. The extra data is not used by Moco, it only considers data in the time range you specify with the initial and final times.

-Nathan

Hi Tomas, I have also looked into this briefly, and the documentation page below should get you started: https://simtk-confluence.stanford.edu:8443/display/OpenSim/Creating+OpenSim+GUI+Modules It's a little outdated, but I have been able to use this general workflow to add an item to the OpenSim GUI...

Is it possible to access a model's mass matrix using Matlab scripting? If so, could someone give me some direction regarding how to do this?

I am manually constraining several muscles during CMC using a CMC_ControlConstraints.xml file. I would like to be able to plot these constraints using Matlab. Is there an existing way to convert the .xml file into something that is easily readable by Matlab, such as .sto?