simtk.org

Hello Everyone,
As you all know Moco 1.0 was released within Opensim 4.2 and before that I was using Moco 0.3.0 with Opensim 4.0.
I re-run my exact same MATLAB scripts that I wrote with Moco 0.3.0 on Moco 1.0 but results are quite different.
Do you have any idea about this difference ?

Moco 1.0 added compatibility with wrapping surfaces for muscles, previous had a bug leading to the wrapping being ignored. Could this explain your difference? Obviously, this is only relevant if your model had wrapping surfaces/geometry to begin with.

Thank you for opinion,
I checked the osim model but there is no wrapping surface.
In my osim model there is only lower body muscles and their activaiton is set to 0.001 in order to mimic paraplegic patients.
I think even if this wrapping object is the case, it should not effect that much the result.

Burak.

Hi Burak,

If you have lower-limb muscles in your model, it is very likely that there are wrapping surfaces. For example, we use a wrapping cylinder to create a more realistic path for the gastrocnemius muscle since it is more superficial than the soleus muscle. These wrapping surfaces have a large effect on the muscle moment arms, and therefore each muscle's moment generation capacity. So in certain cases, I would expect to see noticeable differences in activations.

If still don't think that is the case and can provide more details about the differences you're seeing, then I'm happy to help debug those issues.

-Nick