So I created a pen using the CV curve tool and then rotated it. I wanted to use two materials on it, one for the pen's grip and one for the rest, but when I select the surface points either the material it looks how I want it to, except when I use render view. When rendered, the grip's material either doesn't show up at all, or it shows that material applied the entire pen instead of what I selected.
The same thing has happened for me on a trashcan I made earlier, though I've never had this problem before. I've tried converting them to polygons, but the same problem persists. If I make a polygon from scratch and apply the same material to part of it, it works fine, so I don't see why there would be a problem to the converted NURB to polygon object.
The material I'm using is a simple lambert with a blue color for the grip and an anisotropic gray for the body.