I want to understand better the mechanism of the Hunt-Crossley sphere forces when used to support the body at the feet. Are the forces bidirectional or uni-directional? I ask because when I apply hip flexion moment to the model standing and supported by Hunt-Crossley forces at the two feet, it has d...

Hi Nicos, I followed your idea with the following code snippet that worked to get the CoM position: BodySet bd = osimModel.getBodySet(); int Indx = bd.getIndex("calcn_r"); const auto& lfoot = bd[Indx]; Vec3 FmassCenter = lfoot.getMassCenter(); osimModel.updMultibodySystem().realize(si, Stage::Positi...

Hi Nicos, Thank you very much for your help. I am exploring it; even though the first line: int mbi_calcR = myModel.getBodySet().get("calcn_r").getIndex(); results in the error message; "class "OpenSim::Body" has no member "getIndex"" I am exploring why this is so. Did you use this in OpenSim 4.0 AP...

Hi, I am having difficulty using "findStationLocationInGround()" to output the location of the center of mass of a body segment. Below is a snippet of my code: snippet.c I also tried another version as: snippe2.c In both cases, even though the body calcn_r reference frame moved far from the ground c...

Thanks Ayman. That works. Cheers.
Musa

I use the following snippet of C++ code to save my state variables after an integration/simulation: Storage statesDegrees(manager.getStateStorage()); osimModel.updSimbodyEngine().convertRadiansToDegrees(statesDegrees); statesDegrees.print("forward_states.sto"); The resulting file saves the names of ...

Yes. You are right Dimitar. I was mistakenly using the CoordinateSet in the second argument of the method instead of the CoordinateReference. Thanks for the pointer.
Musa

Declaring assemblysolver object: I read an open-link model from an XML file (skeleton_file.osim). I then added bodies to it so that it will become a closed chain body system after assembly. A snippet of my code is attached. snippet_code.cpp 'weights' vector is to ensure that some of the joint angles...

In the C++ code of ExampleClosedTopologyMechanism of Simbody, a ball constraint was defined using the form: "Constraint::Ball(linker1, Vec3(linkerHalfDims[0],0,0), rocker1, Vec3(0,-rockerHalfDims[1],0));" When I used the same form in my code as: SimTK::Constraint::Ball(parent_body, loc_p, child_body...

Hi, My model file works well in 3.3. However, when I tried to run a simulation with it in 4.0 C++ API, it threw an exception with the following message: --------------------------------------------------------------------------------------- Updating Model file from 30516 to latest format... Loaded m...