simtk.org

I found a really strange behaviour with IK in the new OpenSim 4.0 beta. It looks as if the new IKTool ignores the clamps in angles, giving invalid results.

I attach as an example a clamped model, a .trc experimental markers file and their corresponding IKSetup.xml for the IKTool, for fast comparison. I also attached an unclamped version of the model for reference.

In this example, the right hip clamp seems to be ignored in OpenSim 4.0.

Thanks for reporting, we will have a look and get back to you shortly. 4.0 is still in Beta so we expect some bugs.

Hi, Marcos-

I am not seeing the issue that you identified. I changed the clamped version of your Model, adjusting the hip_roation_r coordinate to a have a more restrictive range (-3 to 3 degees). When I run IK in 3.3 and 4.0, I see the coordinates values constrained between these values. When I unclamp the right hip, the results exceed the -3 to 3 range, which I would say is the correct behavior.

Could you perhaps describe what you would expect when a coordinate is clamped during IK which will help me verify out what you are seeing?