simtk.org

Hello all,

I am running into an issue after scaling that maybe you have encountered and could possibly orient me in the right direction. It might be something simple but I have troubles to figure it out.

I have noticed that for some of my subjects scaling seems ok but for others the hip seems to be too big and in some cases the legs are even too flexed from the start of the motion. I have checked with my analog video and my subject pose is definitely not like this.

I assume it has to do with the experimental markers and virtual markers scale processing. Is there any solution? (is manual scaling for the pelvis the option in such subject's cases?).


Kind regards

Hi Karelia,

The scaling step in OpenSim is really composed of two tasks:
1. computing and applying scale factors to various bodies
2. Perform one-frame IK to line-up the markers on the model with the experimental markers in the static trial.

If the scaling looks good but the pose is bad then it's a problem with task 2 while if the pose looks good but the bodies are scaled badly then it's a problem with task 1.

Hope this helps,
-Ayman