Why modelcurve.Bycurve tool doesn’t work?

I have a very stupid problem and i am not able to fix it.
I hope someone could help me! thanks in advance.

The error message seems to indicate that Model Curves can only be planar

You can only create non-planar nurbs curves in certain Families. For example, if you create a new Mass Family, convert your points to reference points then use CurveByPoins.ReferencePoints() from the Revit library:

Thanks very very much :grinning:@Thomas_Mahon @Vikram_Subbaiah