This fixes T86440
As the CU_2D flag is set for nurbs, a Curve can have 2D nurbs mixed with 3D.
But the UI does not allow this mixing. It updates all nurbs to 2D or 3D when set.
So remove this specific flag for nurbs.
This may break old files, since 2D curves with mixed 3D are now set as 3D.
Differential Revision: https://developer.blender.org/D10738
This patch adds a to_curve method to the Object ID. This method is
analogous to the to_mesh method. The method can operate on curve and
text objects. For text objects, the text is converted into a 3D Curve ID
and that curve is returned. For curve objects, if apply_modifiers is
true, the spline deform modifiers will be applied and a Curve ID with
the result will be returned, otherwise a copy of the curve will be
returned.
The goal of this addition is to allow the developer to access the splines
of text objects and to get the result of modifier applications which was
otherwise not possible.
Reviewed By: Brecht
Differential Revision: https://developer.blender.org/D10354
