PBR metalness equivalent in Vray

[Joezeta]

Does Vray have a matching parameter, or something related, to the metalness map (that distinguishes metals from non metals) found in real time softwares like Marmoset or Unity?

[Laserschwert]

Does Vray have a matching parameter, or something related, to the metalness map (that distinguishes metals from non metals) found in real time softwares like Marmoset or Unity?

Technically "metalness" would be mapping the Fresnel Reflection IOR. So basically you need a mix map where the metalness-map blends between your two desired IORs (black being the non-metal IOR - 1.6 by default - and white could be an IOR of 10 or so). Although I don't even know, how to map IOR values via greyscale values...

I guess it's easier to just use a VRayBlend material, using the metalness-map to mask a bare-metal or chrome material on top of your normal material.

[DaveKW]

I believe a metalness map also looks at the albedo and adds that to the reflection colour based on the metalness amount.

[Morbid Angel]

to map IOR the texture needs to be in float, so whatever part of the object has to be higher then 1, then the texture needs to be representing that or else it will be whatever the value of the texture = low reflection.

[Ihno]

Depends on what you are trying to do.
If you want to use textures which made for that workflow and you simply want to use the metallness map to divide metals from other materials. The easiest way would probably be a blend material with both, non-metal and metal in. And the metallness map used as blend map and specular color. A little fiddling with the output curves and you should be able to get something quite similar.

If you want to match them more or less precisely it gets tricky.
For example if you want to have a test material in max for using max procedurals and nodes to make textures for unity. There are no output curves for the textures in Unity so it needs to be quite accurate.

I tried to match the Unity standard material but in specular workflow mode.
Because its more familiar and less complicated.
I used the measurement method of adanmq as described here: http://forums.chaosgroup.com/showthr...y-amount/page2.
I also made a version of the scene for unity and used a hdri screenshot script and hdr rendering (of course).

I successfully matched the specular strength but totally failed with the glossiness. I spend 3 days trying everything I could Imagine but I couldn't get that curves to match. I'm not very experienced with this kind of work. So, someone else may find out what's happening there. But matching the metallness workflow where the albedo also has an influence on the reflection would be even harder to do.

The Chaos Group is working with some realtime engine developers and I think there will be a solution soon. Most likely a light map baking plugin and a v-ray material for those engines (I'm just guessing).

Today I've seen that the physical material has a metalness parameter. But I don't know if its (at least) nearly the same...

[^Lele^]

A couple of excerpts from the Disney paper on their principled shader, from 2012:

Diffuse reflectance represents light that is refracted into the surface, scattered, partially absorbed,
and re-emitted. Given that some of the light is absorbed, the diffuse response will be tinted with the
surface color, and any portion of a non-metallic material that is tinted can be considered to be diffuse

metallic - the metallic-ness (0 = dielectric, 1 = metallic). This is a linear blend between two
dierent models. The metallic model has no diuse component and also has a tinted incident
specular, equal to the base color.

So Dave is right, provided the diffuse turns black.
In essence, a one-liner would say you make a dielectric into a metallic if you blacken the diffuse, and tint the reflection.
Matching specular lobes is then a case of parameter mapping and identical BRDF implementations (ie. a bit of a hit and miss, currently, still.).

[vlado]

So just to update this topic, we have a metalness parameter in the VRayMtl material now for V-Ray Next.

Some more information here:
https://docs.chaosgroup.com/display/VRAY4MAX/VRayMtl

Best regards,
Vlado

[Morne]

So just to update this topic, we have a metalness parameter in the VRayMtl material now for V-Ray Next.

Some more information here:
https://docs.chaosgroup.com/display/CWVRAYMAX/Metalness

Vlado

Cool thanks guys!

...I seem to be getting a video unavailable error on that youtube link however

[KristinIvanova]

Cool thanks guys!

...I seem to be getting a video unavailable error on that youtube link however

Thanks for noticing! It is fixed now.

[Morne]

cool, looks very handy