Custom model.

[Andrea Morelli]

I try to customize gait2354_symbody.osim file adding r arms.

This is an example code i added:

<SimbodyBody name="humerus_r">
<mass>0.000000000000</mass>
<mass_center>0.000000000000 0.000000000000 0.000000000000</mass_center>
<inertia>0.000000000000 0.000000000000 0.000000000000 0.000000000000 0.000000000000 0.000000000000 0.000000000000 0.000000000000 0.000000000000</inertia>
<VisibleObject name="">
<geometry_files> humerus.vtp </geometry_files>
</VisibleObject>
</SimbodyBody>

When I open the file with my changes, software crash without any error message.... Where I'm wrong ?

I try to add only one object and the same...
Thank you for you help.

Andrea

[Sam Hamner]

Hi Andrea,

When you create new segments for a model, you must also create new joint definitions and the corresponding generalized coordinate(s) (e.g., joint angles), and generalized speed(s) for that segment.

I have created a model with "simple arms" using gait2392. Each added upper extremity has 7 degrees of freedom (3 dof shoulder, 1 dof elbow, 1 dof pronation, 2 dof wrist). Perhaps you could use this model as an example of how to build upon an existing model. I have posted the model on my SimTK project here: https://simtk.org/docman/?group_id=252

Additionally, the OpenSim team is currently working on simplifying the format of the model files (i.e., the xml code), which can be cumbersome to edit. The new model format should be released soon with the next version of OpenSim (v 1.6). The new version will automatically update older models to the new format.

[Andrea Morelli]

Thank you for the help Samuel.
I've downloaded your model and I'm looking at the code to understand the workflow.

Thank you
Andrea

[Joseph Alston]

Samuel,

Could you also post the geometry files that you used?
I trying to create a model of a 50th percentile male in order to look at head and neck movement while running. I just started, so I'm hoping to learn all I can from other people's models.

Joseph Alston
U of U

[Sam Hamner]

Hi Joseph,

Do you mean the *.vtp files that are used to visualize the skeleton? All of those files are included in the OpenSim download. To find them, go to the directory where you installed OpenSim (e.g., C:\Program Files\OpenSim 1.5) and look for a folder called "Geometry." All of the *.vtp files to visualize the skeleton are in there.

If you mean the physical "geometry" of the skeleton, all of that information is included in the model file (*.osim).

[Joseph Alston]

Ya, I meant the *.vtp files. I looked for the files that you used, but they have a r_ of a l_, at the beginning of the name depending on if they are for the right or left side of the body. The files that I have in the recently downloaded geometry folder that I have has a different nomenclature. That is why I was wonder what file you used.

[Sam Hamner]

Hi Andrea,

I hope the model with arms has been helpful. I created the model for my own research project and have just updated the citation on the download. If you end up using the model for your research, please cite:

Hi Pablo,

Glad it worked!

I have created this model for my own research project, and have just updated the citation. If you end up using the model for your own research, please cite:

Hamner, S.R., John, C.T., Anderson, F.C., Higginson, J.S., Delp, S.L. Reducing residual forces and moments in a three-dimensional simulation of running. North American Congress on Biomechanics (NACOB), August 2008.

Thanks,
Sam

[Sam Hamner]

oops! sorry for the extra stuff. i was too fast with the cut and paste.

[Andrea Morelli]

Hi Sam.
Sure I will!

Thank you for you help.

Where i can find your ref ? I think It will very interesting to read.

Thank you again
Andrea

[Sam Hamner]

Hi Andrea,

Sorry for the delay in reply. I have uploaded a copy of my poster from NACOB, here: https://simtk.org/docman/view.php/252/1 ... rNACOB.pdf

Thanks,
Sam