Freezing while Adjusting Marker Data

[Chris Kain]

I have been trying to scale a generic full body model in to experimental marker data provided by Dr. BJ Fregley (U. Florida) for a class project. When I only select the "Scale Model" box in the scale tool and make the necessary adjustments (renaming / repositioning markers, etc.), it works fine. But when I select "Adjust Markers" box, with or without the "Scale Model" also selected, and run the scale, the green status bar appears at the bottom with the "executing scaling" message, but never finishes. This has happened with my model on multiple computers, so I think it is something wrong with my model. I attached the scale settings (.xml) file. I would greatly appreciate any feedback, as the project is due next week and this is a sizeable roadblock.

[David John Saxby]

Hey,

I've had that problem when I turned off the model scale and tried to only use the reposition/adjust markers process.

What I usually do is leave the scale model process active, but set the scale factors to unassigned or manual scales of 1. This keeps the model from being scaled (if that is what you want).

Check the static pose weights and make sure the markers and/or general coordinates are being tracked. As I understand it, the minimization cost function has two terms in it (potentially). 1) the squared error between model general coordinates and experimental joint angles (if you are applying from a file), and 2) the squared marker error between virtual markers at a given joint angle and the experimental markers. If you aren't tracking either joint angles or markers then the process can't find a solution.

Hope that is of use.

David

[Chris Kain]

Thanks David, turns out scaling the model to 1 while adjusting markers at the same time was the way to go. Not sure why...

[Ayman Habib]

Thanks David for the helpful workaround.

It would be good to have a bug report with all the model/data/setup files needed to reproduce this bug so that we can have it fixed in the next release without the need for workarounds.

Best regards,
-Ayman

[David John Saxby]

Hi Ayman,

I'll post a bug report and include the model, setup files, and data.

David