Author Topic: Arnold 5, specular color/weight for non metals.  (Read 2882 times)

Hi all

I have been making some tests with Substances and Arnold 5.
So far my biggest doubt is the value to give to the Specular Color (or specular Weight parameter as it is a multiplier) when you are dealing with a non metal material or a partially metallic material like a rusty metal.

I assumed at the beginning that the correct way was to leave both Specular Weight and Specular Color set to 1 and "white", as the Arnold 5 guide says: "When Metalness is enabled, the Specular Weight and Specular Color only control the edge tint, while the Base is still affected by roughness."

Since in the PBR workflow from substance there is always a map connected to Metalness, even if the map is black Metalness SHOULD BE enabled (although maybe for enabled they mean a non fully black map, this is really unclear to me).

Since I am dealing with non metallic substances (a roof, a  patch of mud and rusty metal), I assumed that specular color and weight would have had no influence on the material.
However the results from leaving specular set to the max were way to bright though for a correct realistic PBR.
So I made a wedge of 3 different substances(a roof, a  patch of mud and rusty metal) with a specular value of 1 (max), 0.25, and 0.
The result shows clearly that the specular value does influence the look of non metal materials a great deal, as shown by the images I linked, which are the beauty, the diffuse pass and the specular pass. Not only in the edge tint of the metal bits (as shown in the rusty substance) but also everywhere.

Am I doing something wrong?
Given these results, my question is:What is the correct value to give to the Specular Weight/Color parameters for a correct PBR?

Many thanks
Paolo
Last Edit: March 03, 2019, 02:24:36 am