When I mask metallic surfaces, I get hard specular spots no matter how smooth the shader is transitioning. Is this normal? Even at AA7 PNT 0.025. This was happening on the razor crest model and many others. I wanted to apply dust and I'd figure I could just "overlay" a material and it just lessen the effect of the shine rather then break it up.
Here is an example. Without the dust layer on the metal it's pretty much fine but with dust it breaks up around corners (like the engine)
You can use a metallic map to do that. Anything white is 100 percent metal, black is dielectric, gray values for anything in between.
Oh... well, duh, huh? Lol I should have thought of using the mask to subtract form the metallic map.