For scaling, as I mentioned prior, if all else fails just go with height. But if you have a full-body marker set you can scale things more precisely. For example, with the vertebrae, you would be better off scaling relative to a C7 to PSIS distance (for y), a C7 to sternum distance (for X), and a sh...

Good deal! Glad it worked. - We scale using Matlab API scripts only to streamline things and minimize input errors, but you get the same results. - I think it sounds like you are assigning the markers correctly. I originally asked/meant if you were just placing the markers on the model without regar...

Hmmmm.... definitely not how the model should look! Without having all your scale settings and markers available, my first response is to just ask you to reopen the model. We have noticed that sometimes the model appears to scale incorrectly immediately following scaling (when using the GUI) because...

https://simtk.org/projects/spine_ribcage
Please see simtk site for a thoracolumbar full-body model.
Jake Banks

Joao, I'll try to answer your questions, but I may need to get back to you on 1-2 items (I'm a fairly new postdoc to the lab/project, and was not around when they assembled the full-body model). 1- my understanding on excluding the arm muscles was/is that they do not play a major role in estimating ...

Not for all (you want the muscles to do things)!!!! Just the 6 Pelvis (3x Forces and 3x Moments, make min and max's ~1000 in magnitude... huge overkill for moments) ones so that there is a reason for the model to be staying at 0,0,0 and not falling. I suspect this is your issue... otherwise I'll nee...

The model is/should be symmetrical. You can always double check this by looking at the model specifics in opensim or via a source code editor. Therefore, I hypothesize 1 of 2 things: 1. Your 'motion' isn't as symmetrical as you think. 2. Your actuator(s) on the pelvis are not large enough to fight g...

Your .mot file had some little errors in it. It had the incorrect number of rows (should be 101), an extra/redundant L4/L5 AB column (I think that was the column), and blank values in the ankle coordinates. The latter error is what caused things to really crash. I could tell something was wrong prio...

I would need to see the .mot, setup file, actuators file, and model.
By 'loads fine' do you mean you can get it to manipulate the model?
Jake Banks

It's pretty difficult for me to say without knowing what your doing/running.
Jake Banks