Muscle Analysis

[Thomas Uchida]

In case you haven't contacted Ajay yet, this issue appears to be related to a bug in 3.3. Sorry I didn't know that. Here's the GitHub issue:

MomentArmSolver was assuming vector of mobilizedBodyForces equivalent to the number of OpenSim bodies, but we are allowing Joints to be composed of multiple mobilized bodies internally and consequently, the size was wrong. The fix was to use the system sized vector of mobilizedBodyForces.

Dimitra Blana discovered this bug trying to plot moment-arms in 3.3 (and 3.2) for the Scapulothoracic joint (plugin). The moment-arm calculation in 2.4 was different (i.e. there was no MomentArmsSolver).

This issue should be fixed in 4.0.

[Kathleen Lewicki]

Hi Tom,

Thanks for following up. I had already contacted Ajay and he was aware of the problem so he's going to help me out and see if there's a way to get the fix to me. I really appreciate your diligence and quick responses to all these questions.

Thanks again!
Kathleen

[Pierre PUCHAUD]

Hi,

I'm getting the same error for the same problematic on musculoskeletal model using the scapulothoracic joint.

Code: Select all

SimTK Exception thrown at SimbodyMatterSubsystem.cpp1090 
  Error detected by Simbody method SimbodyMatterSubsystemmultiplyBySystemJacobianTranspose() The supplied spatial forces vector had length 33; expected 37. 
  (Required condition 'F_G.size() == nb' was not met.)

Thank you both of you for your pieces of advice. I was wondering if there is any updating concerning this issue on computing moment arms ?

My second question is, when the opensim 4.0 will be release ?

Best regards,

Pierre.

[Gabriel Oliveira]

Hi everyone,

I am getting the same error too.

If you have some new about it, please let me now.

Thank you