simtk.org

I have a human lower limb model with muscles, contact spheres and a markerset. I'm using versions 4x (have tried 4.3 and 4.2 - same issue in both). Every time I go to Tools > Scale Model, opensim will crash (I don't get any further than clicking on 'scale model' in the drop down menu). It doesn't do this when I open up the example models, just with my own data. Could I have done something wrong elsewhere when compiling the osim model that I'm not aware of? If I revert to an earlier version of the model which only has muscles and contact spheres (no markers), it will let me get to the scale popup box without any problems. It seems to be the markerset that is causing the issue, which is compiled as follows:

</ForceSet>
<!--Markers in the model.-->
<MarkerSet name="markerset">
<objects>
<Marker name="L_PSIS">
<!--Path to a Component that satisfies the Socket 'parent_frame' of type PhysicalFrame (description: The frame to which this station is fixed.).-->
<socket_parent_frame>/bodyset/Pelvis</socket_parent_frame>
<!--The fixed location of the station expressed in its parent frame.-->
<location>0.076224405341382639 -0.10118675766715654 0.12067830088426777</location>
<!--Flag (true or false) specifying whether the marker is fixed in its parent frame during the marker placement step of scaling. If false, the marker is free to move within its parent Frame to match its experimental counterpart.-->
<fixed>true</fixed>
</Marker>
</objects>
<groups />
</MarkerSet>

Thanks for the help in advance!
-Ashleigh

Hi Ashleigh,

Considering that other models with markers scale without an issue, including models in our distribution I doubt that this is the issue. Please open a bug report and attach a zip file with the model, meshes for contact and necessary files for scaling and we'll check them out. Can you do manual scaling using made up scale factors? Can you visualize the static-trial data?
These steps may help us isolate the issue.

Best regards,
-Ayman

Thank you, Ayman

I've submitted a bug report just now with the data. Hopefully someone can help

I'm unable to get to the scale popup at all. As soon as I use the drop down menu to open up the scaling tool, it crashes.

Best wishes
Ashleigh

Ashleigh,

The body R_thigh in your model has no mass, which ends up being NaN and causes a crash downstream when trying to make a copy of the model to scale it. Setting the value to a number, fixed the issue. Please let me know if that gets you around the problem. I'll open an issue to make sure we handle this more gracefully and give informative message rather than crash.

Best regards,
-Ayman