Preview Marker and Force Plate Data Simultaneously

[Aaron Henry]

Hello,
I am currently implementing the sheep hindlimb model (https://simtk.org/projects/sheep_hind_limb) with my own data set. I have successfully previewed experimental marker data and force plate data within the GUI. I have also associated force plate data with the model after running scaling and inverse kinematics. However, when associated the motion data with the scaled and IK model the model is shifted left (-z direction) such that graphically the foot strike and force vectors do not properly align. I have 2 questions regarding this issue.

1. How can I prevent my model from shifting such that when I associate force plate data with the inverse kinematics results, the model appears to be stepping on the correct force plate.
2. Is it possible to preview both marker and force plate data simultaneously before implementing any data into the model?

Image of force vector offset from model after scaling and IK: https://i.postimg.cc/5tT5F9Vc/Model-Offset.png

Thanks.

[Aaron Henry]

I have just found the 'Sync Motion' option in the Navigator window which is what I was looking for. However, I am still having issues aligning the marker motion with the correct force plate vector. The force plate vector has been rotated correctly, but is still translated too far away from the marker data.

[Ayman Habib]

Hi Aaron,

The GUI does not add offset to experimental data so these should line up, if not I'd suggest you check the raw data and open a bug report if incorrect. Models can have an artificial offset added for display purposes to make sure multiple models do not overlap. You can control that by changing "Display->Model Offset" from the context menu that you obtain by right-clicking the Model's node in the navigator panel.

Please let us know if that fixes the problem.

Best regards,
-Ayman

[Aaron Henry]

Hi Ayman,
Changing the model offset helped me fix the visual display of the scaled model and force plate data. However, there still appears to be an issue with offset of the raw force plate data (.mot file) when loading it in as experimental data. I have taken a look at the raw data file and the GUI is not displaying the correct point locations of the force plate data. I will submit a bug report detailing this.
Thanks.