Thank you for the detailed responses Sherm! Though now our two systems behave differently. When I update line 128 to this modelState = new SimTK::State(model->initSystem()); I get a segfault at this line when the program is run. In addition, when I change modelState from a pointer to an object SimTK...

I pulled from the master branches of both OpenSim and Simbody on git hub, so I should have:
OpenSim 4.0
Simbody 3.6
As a double check I looked at the version numbers mentioned in doxygen, and everything is consistent.

Cheers, Matt

Hello, I would like to use an OpenSim model with an optimal control code. The OpenSim header file and the header file of the optimal control code do not play nicely together. In an effort to isolate the two codes from each other I've made a separate class for the OpenSim model (OpenSimPendulum) and ...

Hello Frederic, As far as equilibrium vs. acceleration model is concerned in almost all cases the equilibrium model is a better choice: it will give you the same answers faster. If you're doing optimal control the acceleration model is a better choice because you can make fiber length, fiber velocit...

Hello Frédéric, Have you checked the fiber lengths and the value of the active-force-length multiplier? My guess is that the normalized fiber length is less than 0.6 or greater than 1.5. In these regions the active-force-length-curve of the Millard2012 model is substantially weaker than the Thelen20...

I think I see the problem: Tug Of War is completely defined in its *.osim file, and so everything about that model is hidden from you in your C++ program. To learn how to edit a model there are two paths you can take: editing the model using the C++ api, or editing the model using the OpenSim GUI + ...

Perhaps I should back up a bit: what programming language are you using?

1. Make a new temporary FiberForceLengthCurve object using the detailed constructor: FiberForceLengthCurve fpeCurve = FiberForceLengthCurve ( strainAtZeroForce, strainAtOneNormForce, stiffnessAtLowForce, stiffnessAtOneNormForce, curviness ); *Make sure you check out the doxygen for the FiberForceLen...

I wholeheartedly agree - it should be clearer which models implement the 'ignore' flags and which do not.

Hello Ilan, Responses interspersed ... I've been running a forward dynamic simulation with constant prescribed activations with four muscles. I used Millard2012EquilibriumMuscle and set the flag "ignore_activation_dynamics" to true, and created a PrescribedController with Constant functions which eq...