I’ve posted my problem here: http://forum.anyscript.org/showthread.php?p=18974
I use an upper extremity marker set to drive my model of the trunk and right arm. I proceed to use the MotionAndParameterOptimizationModel and the InverseDynamicModel to calculate Joint Loading. When I switch the ‘OptimizeAnthropometricsOnOff’ on for the UpperArm and LowerArm the Elbow joint is disconnected after the Optimization. Because I do not know each segments length exactly, I need the Optimization to complete my movement (maximal reaching task). Otherwise the motion is not followed completely and the arm is not fully stretched or goes into gimbal lock.
I’ve also noticed an error in which the humerus is rotated 180 degrees. The Elbow C3D marker is shown on the medial side of the body and the humerus is rotated so it fits with the AnyBody marker. However the C3D marker is placed on the lateral epicondyle, so I don’t know why the humerus is twisted.
I’m informed that the typical solution would be to add some soft constraints to limit the rotation of the bones. However, I’m afraid I do not have the necessary skills yet to do this in a short time. I’ve registrered for a course later in March, but this will be too late for my deadline.
Because I tried some marker replacement I can’t find the disconnection of the elbow at the moment. However, I’ve added the twisted Humerus file to the model.
I’m using the AnyBody version : 6. 0. 4. 4327 (64-bit version) with folder AMMR.