So with metal roughness PBR workflow, are anodized finishes Metal or non metal?

CognizanCe

Most metals I see are conservative shades of gray, bronze, or gold.
If someone wanted "out there", funky colored metals that are grounded in reality, can anodized metals be used as reference?

stuff like this:










-Or is it just a coating, and therefore a non metal?

huffer

In those cases, yes, treat them as metals, they should be white on metalness map, or the respective funky color if you use specular. You can tell if it's a metallic finish if the specular highlight is also colored (in most cases).

JordanN

I looked up what anodizing is and found this:

"Many metals are structurally weakened by the oxidation process, but not aluminum. Aluminum can actually be made stronger and more durable through a process called 'anodizing'. Anodizing involves placing a sheet of aluminum into a chemical acid bath, quite often acetone in laboratory experiments. The sheet of aluminum becomes the positive anode of a chemical battery and the acid bath becomes the negative. An electric current passes through the acid, causing the surface of the aluminum to oxidize (essentially rust). The oxidized aluminum forms a strong coating as it replaces the original aluminum on the surface. The result is an extremely hard substance called anodized aluminum. "

Technically, there's a metal that's on top of another metal. So that's two layers. But in PBR, any metal that is rusted is not metal anymore, and the anodizing process seems to be based on that (aluminum that has been rusted that's used to coat another metal).

I also found a picture of what happens when you remove/scratch the surface of an anodized object and the protective layer stays the same whereas the bottom layer (the real metal) gets oxidized/rusted.

pior

As per usual with PBR stuff : do not overthink it. In practice it takes about 1 second to setup.


Good luck !