Big problems with scaling

[Anthony Ligouri]

I am trying to scale a full body model in the same way I scaled the gait2354 example model and am having a major problem. I have all my scaling files (trc with global reference frame the same as the opensim global frame, tasks file, measurement file, and set up file) and I load the settings as opposed to using the scale tool GUI every time. I make sure to check the Preview static pose (no marker movement) box before I run it. Once I run the scale tool, and the scaled model appears, the virtual (pink) markers are all over the place and are nowhere near the experimental (blue) markers. Also, only a few body segments actually appear. The experimental markers from the trc file are al correct with respect to the ground coordinate system.

Does anyone know what causes the scaling to fail like this or where I could start trouble shooting? I have looked over my scaling files but nothing is popping out at me.

[Anthony Ligouri]

Also, if I close the new scaled model and reopen it, everything appears, but if I try to scale this model I get a run time error and OpenSim crashes. But since I can not check my marker error at this time, the model is useless anyway.

[Ayman Habib]

Hi Anthony,

Regarding the disappearing geometry during scale, that was caused in earlier versions (or computers that had earlier installs of OpenSim pre 3.0) because the geometry path used by the GUI was relative. We switched to use absolute path in 3.0. Please modify the use preference GeometryPath to include the absolute path to where your geometry files are located and you'll see the geometry after scaling.

For other scaling issues I'd say try a reduced set of measurements first then grow it to include your full set in order to identify which measurements/markers are problematic.

Did you try to preview motion data on the trc file to see if it has the correct orientation?

Hope this helps,
-Ayman

[Anthony Ligouri]

I was doing this in version 2.4. I installed 3.0 and this problem did not occur. Thanks for your input. At least you know a potential problem from 2.4 has been taken care of in 3.0.