Epic Games / Disney White-Washing

[Deathrey (DeathreyCG)]

@Rawalanche

Did he?

He was not the first and likely to be not the last from whom I’ve heard about it. Different artists word it differently. Over bright-specular at an angle, wax-like appearance, white sheen, plastic look.

@Rawalanche

Or is it just the way you’ve interpreted his somewhat cryptic formulation and associated it with an issue you have with UE4?

Maybe. Or maybe not. In view of a sentence above, I’d lean towards the latter. I do not have any issues with UE4. In fact, the matter is not specific to UE4.

@Rawalanche

What you are likely referring to has been known as rough/glossy fresnel: https://www.chaosgroup.com/blog/unde…glossy-fresnel , a formula made to correctly compensate for diffusion of reflective energy on the grazing angles as the roughness increases…

Nope, I am referencing to visibility term and associated issues with using it on pre-integrated data. But the nature of complication, in response to which it was introduced in vray and then in the other renderes, is the same.

@Rawalanche

BUT!

I have been using offline renderers lacking proper glossy fresnel implementation for years, and once both of them finally got it (Corona and V-Ray) the difference was obvious, although not big. Non the less, I can spot lack of glossy fresnel implementation when I see one, and it certainly does not concern unreal engine. You can tell absence of it if you make highly specular, highly rough completely black material and then put it into bright environment. If the glossy fresnel compensation would not be present, then you’d end up seeing very obvious bright ring around the grazing angles, yet when you try that in UE4, you get the right result:

If Unreal did not implement any handling of glossy fresnel, you would literally see something looking like this, cause that’s exactly what I saw when I was using renderers without glossy fresnel:

I would not doubt your experience for a split second, but glossy fresnel, as you know it, is not present in UE4. And it should not be there in the form familiar to you know from offline renderers.

If you ramp up and isolate spec IBL contribution high enough, you will see it on a rough sphere.

https://i.gyazo.com/5e84fb0e252cf1ed341d24b888c968a5.png

@Rawalanche

So if you feel like your speculars on rough materials are too strong, then it’s most likely just your subjective unrealistic expectation of how the material should look under given lighting conditions, rather than issue with the material implementation.

I claim only that indirect specular contribution for rough surfaces deviates from expectations and that it plays a role in artists complaining about it occasionally. The issue is not with specific implementation or engine, but theory behind it and I am not basing that on personal experience or, in fact, anything subjective.

@Rawalanche

And if you are doing some fake things to fix that, you are most likely breaking it instead

The way I am doing it certainly breaks things.Dampening fresnel for indirect spec is a patchup without any theory behind it in response to artistic issues.

@ZacD

I wonder if “normal map mipping error” contributes to the white reflective dirt issue? I don’t know if UE4 addresses this in any way.

http://media.steampowered.com/apps/valve/2015/Alex_Vlachos_Advanced_VR_Rendering_GDC2015.pdf (page 28)

It does.