John, this is something I have been exploring using different implementations for modeling backpack load sharing: https://www.researchgate.net/publication/344446620_A_backpack_load_sharing_model_to_evaluate_lumbar_and_hip_joint_contact_forces_during_shoulder_borne_and_hip_belt_assisted_load_carriage...

Hesam, I am able to use the CMCTool() method and configure the related properties just fine in both the 3.3 and 4.2 API using MATLAB or Python. Can you attach the code that is giving you an error so we can give some more specific advice? This sounds like you are missing the "import org.opensim.model...

Hi Yu and William, I was just struggling with the same issue in trying to adapt some materials to the 4.1 API, and I think I got everything to work for me. I have a few items left on the todo for this as the default coordinate function in the TransformAxis is apparently a constant "0". This just mea...

Hi Mritula, I've done something like you are trying using 3.3 through Matlab. Comparing to the code you posted, I believe you have one extra line in the for loop causing your problem. segScale(i).getScaleFactors(vec); %scaleFactor as input- eg[1.1 1.1 1.1] This line is reading the default values in ...

Hi James, thanks for responding. Apologies for not stating units in my initial post. The tracking error was plotted in radians, so this is close to an 3 degree error (using increased tracking gains). Below is a plot of the original right knee angle compared to the tracked one from RRA (this plot sho...

I've just started working with a model using the Lai 2017 / Rajogopal 2016 lower extremities along with the Senteler 2016 lumbar spine and am encountering a unique issue that I have yet to make sense of the cause. When running RRA there is an initial period of time where the knee angle tracking erro...

All, I've recently come across the same (or similar) problem. Using OpenSim 3.3 on Windows 10 64bit, whenever I tried to open any file within the gui, the software would shut down. This would happen before even selecting a file to open, simply after telling OpenSim I wanted to open a file. Following...

UPDATE: This problem seems to be related to the upper stiffness of the coordinate limit force. I didn't remember at the time I posted, but I had issues running RRA until I put in an upper stiffness as well. If I give it any value, even 1.0, the analyses will run. I don't understand why this is an is...

I've been working with a model trying to use a coordinate limit force as the constraining element between a backpack and the torso, which currently has a single DOF joint. I can run RRA with the coordinate limit force enabled, and I let that drive coordinate values for the backpack joint. When I the...