I made a brake disc with bezier curves, and I want to make a material for it. Should I convert it to mesh? If not, how can i set the position of the texture?
The texture coordinates are pre-defined for bezier curves, you cannot assign UV coordinates. You can use only “Orco” coordinates (maybe other types as well, I have not tried them.)
If you want to use UV coordinates you must convert it to a mesh, if you don’t need UV coordinates I recommend leaving it as a curve. If you do convert it to a mesh I recommend that you separate all the different curves that make up the curve object and convert them to mesh separately. Them join them together as mesh objects and use F < Skin face/Edge Loop tool to fill in between the curves. The reason I suggest this is because converting a curve with multiple curves to a mesh object results in a poorly created mesh with lots of triangles.
It seems I’ll use “object” texture coordinates with empty, so I’ll leave it as a curve.
NURBS are great for modeling curved surfaces because you can make large scale adjustments fast. Poly are quicker to render though, so NURBS are often converted before the renderfarms.