Hello Michael.

thanks for the reply!
Important for me was this:
var pln=ofFac.getCurvePlane();
ofFac.setInput(1, dist);
ofFac.setInput(2, pln);

I've displayed the pln frame in the nodeeditor and now I know what to do, to filp the side of the offset (I don't have a pointpicker here!).

Have a nice day
Karsten