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Hello,

I am trying to troubleshoot CMC on a spine model of the pelvis up to L1. The model does not include muscles and therefore I am only using reserve actuators to produce desired kinematics. However, CMC has not been able to converge to a solution and I get this error message:
I have been playing around with the control constraints and the optimal forces of the residual actuators and I haven't been able to find a solution to the problem. The only instance in which CMC was able to converge was when I modified the body masses to near zero (0.0001 kg).

I am hoping someone has an idea of what my issue might be here and how I can solve it. Thanks!

If CMC starts but doesn't run to completion, the issue may be due to the accumulation of numerical/tracking error. Loading the partial results file and playing the motion or plotting the coordinates may reveal an obvious deviation from the tracked motion. In this case, adjusting the tracking tasks and/or reducing the cmc_time_window property may help. Depending on the situation, adjusting other parameters in the CMC setup file (e.g., tightening/loosening tolerances) may also help.