Constraints can receive local directions. Wherefrom does the constraint take its local direction or how can I influence it?
If a spring or a coupling receives a local direction, this information refers to the coordinate system of the structure point at the beginning of the element. If there is no structure point there, a point with default settings is created internally during the export and its directions are used.
To be on the safe side, you should always create a structure point at the starting point for local directions and align it if necessary.
thanks for tht information, but I can not see any impact in my example when I turn the direction.
What am I doing wrong?
Try to create the effect using a small example. Couplings where the direction is important are, for example, couplings where moment hinges are released.
I have tried this with the coupling global X+Y+Z. Attached two pictures, which should clarify the procedure. In the first picture you can see in which direction the coupling was defined, in the second picture the moment from a single load in the middle of the field of the bolt.