PBR safe base color node in Designer?

gnoop

I found  the node in Designer  that makes safe colors from input .  While how it behaves on whites is perfectly what I expected , its clipping on dark end seems a bit too extreme for me.  Nothing looks  kind of enough  black with this in our game.  Especially some artificial materials  of black nature. Always a bit washed out.     Wonder do people follow what that node does at  zero tolerance ?   For example  RGB 33,33,38  is too dark obviously .    The node also desaturates  too vivid  colors.   We did it before  modern advanced color transforms like ACES.  Seems a bit of redundancy now? 

poopipe

Maths wise, the low end is really the only thing that matters for diffuse .  
( And metallics shouldn't ever be fully saturated ) sooo.. I'd make my own node 

Anyway..
Assuming this node isn't crap...

If black looks wrong in game and you don't want to eyeball it, you need a rendering pipeline that can be set up properly -and then you need to set it up properly. 

It is really, really hard to get this working when there's several teams of people interpreting everything differently, not calibrating their monitors, you don't have a colour managed material pipeline and you're working with legacy content. 
It may not be worth it in the end...

gnoop

well, hm. perhaps my  RGB 33,33,38  is tiny a bit under  what charts recommends , Unreal says deffuse reflectance / luminance for charcoal, dark fresh asphalt , dark rubber  should be 0.02    . it's RGB 39 39 39 in 0-255 scale using   typical luminance calculating formula for sRGB   :   0.2126R + 0.7152G + 0.0722B.    and srgb to linear  proper formula.   I usually do just /255  but it's not entirely accurate  so  I asked chatGPT to calculate it. 

  Anyway sRGB  39,39,39 in 0-255  sRGB  is what  charts say.     So why  this Designer node corrects it to RGB 48,48,48.    On my eye its quite some brighter and  does look quite color washed even in Unreal.     Then google AI told me its should be 60 .    isn't it going a bit crazy? 

poopipe

Iirc the node supplied with designer lets you switch between the two  - if you're on the 70 version it's probably clamping your values to what it sees as full black 

Don't ask the AI stuff like this - it can't do sums and it recycles all the misinformation on the internet when you ask it questions . 

The vast majority of people who write about the subject don't understand how it works and just repeat something they heard or read one time.
Those that do understand will always tell you that the correct answer  depends on the specific implementation in your renderer. 

If you're using unreal, follow the guidelines in their documentation. If it's a proprietary engine, find a render programmer and ask them what they expect you to do. 
Once you've done that, it's trivial to make a validation node.  

Eric Chadwick

I found this informative on PBR black levels
https://docs.unity3d.com/2017.4/Documentation/uploads/ExpertGuides/Dark_Dielectric_Materials.pdf

also linked via our wiki
http://wiki.polycount.com/wiki/PBR

gnoop

Eric Chadwick  thank a lot for the link.    I also think  that Designer node de-saturate primery-ish colors. It' s also a bit weird since isn't it   tone mappers   responsibility to do that  in modern renderers ?    

Eric Chadwick

Well, there is no pure color in properly-formatted PBR color maps. And tone mappers can only do great with good inputs.

White paint for example should be no brighter than 240 or so. Snow is the brightest at about 243. A lemon peel is around 220,185,0. 

gnoop

Well , I see how this node changes  advertisement colors  sponsors are are often  keen to preserve as trademarked  

Eric Chadwick

Well as you know, color in 3D is a combination of textures, material settings, lighting, and tone mapping.

I am very aware of color accuracy issues in real-time for e-commerce, being in weekly conference calls with many of the big players in the space. To control color representation, you need to control all four of those ingredients.

Here's a recent stab at handling the tone mapping end of things, for e-commerce needs: https://www.khronos.org/news/press/khronos-pbr-neutral-tone-mapper-released-for-true-to-life-color-rendering-of-3d-products

gnoop

Eric Chadwick    Interesting link . thanks  Eric