Why does this sphere have an outline? I was just doing a render test of Andrew Price's PBR Metal shader and noticed that the sphere I was testing on has a black outline. Is there a reason for this? Is it a render setting, or something to do with the node tree? Obviously this is not what I'm actually rendering, but I'd hate to think such artifacts would slip into my eventual renders.
Just add a subdivision modifier to the sphere and the problem will be solved.It's caused due to low geometry.