Basic question about scalling

[Tim Zulj]

Hey, im kinda new to OpenSim and i read all the basics and documentation about scalling, but i still have one problem.
I used model arm26 and put 3 markers on my arm (wrist, elbow, shoulder), i did the needed transformations (i think so?), because now i have the right orientation of the arm (shoulder marker on the top). Problem is, i still have big offset. Markers on model and my markers are for some reason very far away (picture).

Where do you think lies the problem? Is it bad measurement? My scale factors for upper and lower arm arent the best (0.8 and 1.2). Is it problem in the model arm26? Since only upper part of the arm is red?

Thanks for help

[Ayman Habib]

Hi Tim,

The arm26 model is intended for educational purposes only (a double pendulum) as such it cannot translate. If you want to model upper extremity motion I suggest you look up a model that meets your needs in our library of models or as provided by the user community on simtk.org

Hope this helps,
-Ayman

[Tim Zulj]

Thanks for quick reply!

Ok, so i used different model and when i try it with preview experimental data, offset is still there.
But when i try to scale the model i can't even run it. I have the same static trc file as before, i only renamed markers in trc file so it matches the model (picture).

So obviously im doing something wrong. Any ideas?