Hello, yes, this is correct. Let us use some symbols for these steps: 1) Simulation -> Force, Activation, F_lv=Force / Activation 2) Force_mod=Force+modification 3) Activation_mod=Force_mod / F_lv. Then I will compare Activation and Activation_mod with the EMG data. After all this can I refer to the...

Hello Matthew, Thanks for the answer. Interesting that you work on solving this discrepancy. When do you think the corrected muscle model will be accessible for the OpenSim users? I am now confused how to apply my changes to the model. I planned to modify force values at every time step and recalcul...

Hi all, I am planning to make some changes to Active Fiber Force and then calculate activations for the new force. In Thelenetal2003 there is an equation (10) showing how force and activation are related. Using OpenSim terms, I simplified this equation: Force_active_fiber=Activation*F_lv (*) I wrote...

Hi Ayaj,

all the problems have been solved when I updated OpenSim and adopted my plug-in for the new version.
I had to copy "OpenSim_SimTKcpodes.lib" from the old version to the new \sdk\lib folder, to get a successful build.

I appreciate your help very much,
keep improving the software.

Natalia

Hi, 1. "the motion must be loaded before the plug-in analysis run", I mean in GUI. It looks like a bug to me. If the motion is not loaded before running the analysis (my plug-in), then no output will be saved or the OpenSim will be crashed, while it the analysis has its place (maybe not complete, bu...

Hi again, I have problems with printing out the values for pennation angle, forces and activations , they all appear as zeros . Only fiber length values appear correctly (I guess because it is one of the states and does not require any analysis). After realizing the system to dynamics, I tried to eq...

Thanks a lot Ajay, My plug-in works now. But the reason for my long way to success is not just mistakes in the code. After changing my plug-in according to your advices I still had the same error (Array index out of bounds). But after several tests I found the reason, it looks like a bug to me: the ...

Hi all, I am trying to write a plug-in for OpenSim. To start with, I want to store some muscle parameters such as forces, activations, lengths... Using an example template giving positions for bones as a basis, I am able now to store muscle names and time column correctly but the values for muscles'...

Hi! I am trying to reproduce calculations of active and passive forces and force-length-velocity surface using the fiber length. Most of fibers during different movements have fiber length below the 'optimal_fiber_length' (for example, lower body model, Gait2354). If we use ' function representing p...

Dear Ayman,

thanks for your advices. I can compile the code now, generate and test a modified model.

I would like to test a modified muscle model on a large model, for example Gait2354. Are the source files (*.cpp) available? If so, then where?

All the best,
Natalia