When I render this:
I get mottled dark spots on the collar. I know this is not the material because the mottling is there after the material is removed. I need to know what is causing this. I need a uniform appearance that looks like steel.
I tried recalculating normals and it made no difference.
The problem is on the Mirror modifier. you are reflecting the full collar just to complete the piece that hold the ring. By doing that you are duplicating the whole collar, therefore creating a bunch of duplicated vertices and faces. Delete the botom part of the object on the z axis and you’ll be fine.
That did it, thanks. I do not know how the bottom part of the collar got made, and was unaware of it. I did not intend that it be made or the mirror applied at this point.