Hi Xiaoyan,

Exactly, OpenSim will make inverse kinematics with your Vicon motion (after converting it from .c3d to .trc), so you have to put the same markers in your model as in your Vicon reconstruction.

Nicolas.

Hi James Here is my upgraded model. It is composed of Thelen2003 muscles and just of few massless bodies which describe shoulder movement and which are allowed because of massful bodies connected outboard (according to Michael Sherman). I just change extension from .osim to .xml to be able to attach...

Hi Xiaoyan, Actually you have to add markers manually according to anatomical landmarks. To be able to follow accuratly the upper limb movement, I choose to put markers on xyphosternum, manubrium, C7, T8 and T12 for thorax part, on acromion of scapula, on epicondyles of humerus, on radial and ulnar ...

Hi James, I use the Thelen2003 muscle model which is used in the arm.osim model without any problem... Interaction between muscles and wrapping surfaces are defined differently in muscle <PathWrapSet>, depending on which muscle is concerned. As an example : <PathWrapSet> <objects> <PathWrap> <wrap_o...

Hi Sherm, Thank you first for your quick answer. I post this topic for the problem of massless bodies that I would like to replace by parameterized axis. Thanks to your answer, I know understand well why certain body are not allowed. Finally, I can keep massless bodies with massful bodies connected ...

Hi James, I have updated the "Stanford VA upper limb" model as you suggested. I have even been obliged to modify the articular kinematics which seems to be impossible to reproduce without massless bodies...The Inverse Kinematics calculation is clearly faster but despite these modifications OpenSim c...

Dear OpenSim community,

Is it possible to parameterize a TransformAxis ? Actually, I would like to define an axis which depends on a coordinate with a sort of CoordinateCouplerConstraint.

Thanks per advance,
Nicolas.

Hi James, Thank you for your quick answer. Actually, I have already defined my Moving path point by independent simmplines. However, this point have to move according to two different coordinates. In my example, the x,y and z locations of one of deltoid's path points have to change first according t...

Hi, As it is summarized in the subject, I search a way to create a moving path point whose coordinates depend on several control coordinates. For instance, in the Stanford VA upper limb model, I try to define a path point for the middle deltoid which will move as a function of the shoulder elevation...

Hi James,

First, thank you very much for your quick answer.
As you suggest, I will upgrade this model and I will keep you informed.

Thanks again for your advice,
Nicolas.