Problem on Model Editing

[Yuliang Sun]

Hi eveyone,

I'm a new opensim user. I have some experimental data of running which contain 51 markers of a full body and GRFs. I want to use the opensim full body model to calculate joint torques during running. The problem is I did not use the same marker set of the opensim full body model (FullBodyModel_SimpleArms_Hamner2010_Markers_v2_0.osim) during my data collection. I have simply moved,deleted and added some markers and change their names of the full body model to match the marker set used in my experiment. Is this a correct way to edit the existing model?

I would appreciate if someone can show me the right way to edit a model.


Yuliang

[Ayman Habib]

Hi Yuliang,

To edit markers you have to select them in the navigator window, then you can change the selected markers name, position or the body it is attached to using the Properties Editor window. Please consult the page on Marker Editing on the documentation website at:

http://simtk-confluence.stanford.edu:80 ... ker+Editor

Best of luck and please let us know if you continue to have questions,
-Ayman

[Yuliang Sun]

Hi Dr Habib,

Thank you very much for your relpy. I have edited the Hamner’s full-body model following your instructions.

Now I meet new problems:

1. When I tried to scale model with the option “coordinate data for static pose”, the program got stuck with "executing scaling".




2. If I scaled the model without the option “coordinate data for static pose”, it could get through. The scaled model seemed to be right. But when I used IK Tool with movement trials, its weird that the pelvis of the model rotated approx. 90 degrees in horizontal plane.





Do you know what's the matter here?

Thank you .

Regards,

Yuliang

[Ayman Habib]

Hi,

One key problem with using coordinate data from other source (e.g. motion capture) is that different packages have no common standard regarding the definition of various coordinates, e.g. 0 pelvis tilt in OpenSim may not correspond to a 0 pelvis tilt in another package or even in another model.

Please check that the values you specified for coordinates match the definition of the model you're using in OpenSim and let us know what you find out.

Best regards,
-Ayman

[Sarah Luther]

I am having the same problem, but I'm not really sure what I should be looking for or checking and changing in my model.

Can you help me please?

Thanks,

Sarah Luther

[Sarah Luther]

Nevermind I fixed it. I gave the model more freedom in the pelvis rotation. That may not have been the best way to do it, but at least he walks normal now.

Sarah Luther

[shuyang han]

Hi Ayman,

The link you give is not available for me, I tried several times, it just does not work. Can you save the file and send it to me ? Thank you! My email: shan@iore.net

Hi Yuliang,

To edit markers you have to select them in the navigator window, then you can change the selected markers name, position or the body it is attached to using the Properties Editor window. Please consult the page on Marker Editing on the documentation website at:

http://simtk-confluence.stanford.edu:80 ... ker+Editor

Best of luck and please let us know if you continue to have questions,
-Ayman