https://simtk.org/plugins/phpBB/viewtopicPhpbb.php?f=91&t=7057&p=18635&start=0&view= The above link should answer your question better than I did. In brief, all you can get from SOpt is muscle force. The tendon forces that are "calculated" are not being considered in SOpt, and that is why they do no...

Sorry, I have been at the American Society for Biomechanics conference. How are you computing the Force variables? The Tendon force should be = Muscle force. If they are not, I would trust the Muscle forces from SOpt. There are no passive forces in this model, as SOpt does not consider Parrell elast...

Riza, This always makes me think for minute... so, I could off on my logic without thinking about it too much (and not looking at any notes I have)... but I believe (from https://opensim.stanford.edu/downloads/ChecklistJointReaction.pdf and working off from FBD and the sign on the Compression Forces...

Yes. The JRA analysis is where you get the load estimates you (I assume) are interested in. Fy should be Compression, Fx should be AP shear, and Fz should be ML shear. The parent body should be the superior (as opposed to inferior) body relative to the joint. The Child the inferior. It really doesn'...

I'm not the one to ask (Brett Allaire does most of that for the Anderson group), but that sounds right.
I've attached a picture of how/when the process was explained to me. Hopefully this helps, otherwise I could give you Brett's contact info.
Jake Banks

I would suggest looking at the sample code I provided Riza (a few messages above). That should give you the methods to adjust bodies/joints manually via an API. You need to use OpenSim specific syntax when calling things. Otherwise, try manually adjusting things via a text editor to get a feel for t...

Good deal. Glad to hear it.
Let me know if there is anything else.
Jake Banks

Riza, See if this does what you want... I think it may. Admittedly, I was/am a little rusty with API coding. My current role doesn't require much of it. So, it was fun to piece together old code and be reminded of what I once 2nd nature for me. I recommend using the model I attached in this folder f...

I'm slowly getting there... I think what you suggested does ~95% of what you want it to. However, as you pointed out in an earlier correspondence, the Sacrum rotates about a point distal to the top center from which you reference your angles (see pic). I can't recall 100% why this is, but it is. You...

Did your 'work around' work? I'm admittedly a little confused (still). It seems to me like things are working. The angles/inputs may just not be how things are defined clinically, so you may need to adjust them to match how the model works. Otherwise, it is just a geometry problem. Sorry, for my lac...