I’m not importing any up vectors from Rhino at the moment, only ‘spline points’ and ‘tangents at spline points’.
I could try to import them as well but not sure if thats the problem.
So the up vector is set automaticly by unreal to (0,0,1) right? How would you proceed if you want to animate a looping plane along a spline in unreal (where the plane is really upside down at the top of the loop and does behaves like in the first picture of the post?