Rotate coordinate system of a joint

Hello,

I have motion capture data from a inertial measurement system as angles in txt-files and want to import them in AnyBody in the FreePostureMove-Model.

Because the movement is not right when I import the data, I think I have to rotate the coordinate systems of each joint. I put an example from the left shoulder in the attachment.
If I understood this image right, I have to use the first sub-image.

So I tried this at the interface:
AnyFolder &gh=…Seg.Humerus.gh;
gh={
AnyRefNode RefNode = {
ARel=.ARel*{{0,0,1},{0,…Sign*-1,0},[{…Sign1,0,0}}RotMat(-90pi/180,y)RotMat(-90pi/180,x);
};

but this seems not right. :slight_smile:

In addition, at my mocap system the definition of the direction of the movement is the other way round than at AnyBody: Flexion<0° and Extension>0°.

Maybe someone can help me with my rotational problem. :slight_smile:

Kind regards
Julika

Hi Julika,

Your email did not have this extra information that you’re changing the joint frames to be able to import your motion capture data.

This is indeed a lot of work! and on the face of it I really don’t think it is necessary.

Instead of changing the default frames in the model, why don’t you create a new anykinrotational measure between the existing humerus and scapula and then drive this measure using your experimental data?

Regards
Ananth