3ds max 2020 | V-Ray 5
This material setup is using V-Ray 5, but will also work for V-Ray next,
And in previous versions, not having the Metallic property, it can be implemented by unchecking Fresnel Reflections and setting the color through the Reflection color.
This technique can also be implemented in V-Ray for other 3D software like V-Ray for Maya etc.
The idea is simple:
Use a VRayBlendMtl to additively combine 3 anisotropic metallic materials,
Each of which reflects a pure primary RGB color, but has a slightly different anisotropic angle.
The additive combination creates an anisotropic reflection that “spreads” the color of the spectrum.
Note that in this example we use Anisotropic Rotation values of 0, 8, 16, but this may change with different roughness and anisotropy values.
For the materials Diffuse Color property we set levels that will combine to create the general brightness and tint of the metal, and the materials Reflection Color is set to 100% so they will combine to pure white reflection at grazing view angle.
For example, if you want the general metallic color to be a yellow RGB: 255, 186, 57, than the first red metallic component material would have a Diffuse Color of 255,0,0, the second green metallic component material would have a Diffuse Color of 0,186,0, and the third material, that adds the blue metallic component would have a Diffuse color of 0,0,57, so the combined blend will have the desired general color.
More info about the VRayMtl Metalness parameter