Texture sheet in PBR

HAWK12HT

Hey hi all, so what I am unable to understand is making texture sheets with different materials like wood, cloth and metal for example on same texture. As per learning material on PBR you are making albedo, rough/gloss and spec in a way that it relates to the surface you want like metal = white wood = black in specular slot. Cool in theory but then we have settings in shaders too in form of sliders that we can tweak so why do we have those when we are making all textures in first place.

I tweak a slider and my metal looks great but it messes up my wood for example. Hope I explained it clear enough.

Obscura

I tweak a slider and my metal looks great but it messes up my wood for example.

This is why you should tweak your textures until they look good without touching the slider. Or alternatively you can use individual materials for the different surfaces but that would result more drawcalls and texture samples. So it works pretty much the same as earlier.

HAWK12HT

hmm so you mean that we dont use the sliders at all? I mean sliders are there and they help in changing settings quickly too. Aye different materials = more draw calls that is why I got myself into thinking effective way of making texture sheets now vs old school method.

Obscura

Well, sliders can work if your maps are mostly accurate and you want just small changes, or when you have only 1-2 or similar material surfaces in your texture. Lets say you have chrome which would have roughness around 0-0,1 and a wood which would be more than 0,5-0,6 in your texture. Lets say you want to make the wood more rough with the slider. it will make the chrome rougher as well. And if you would have a concrete and a wood surface for example, then the slider would probably work. So the case selects if it works or not, but mainly doesn't because you usually want more than 1-2 surface types.

HAWK12HT

Ahan that is exactly what is going in my mind, so far the alternate I see is defining materials in environment and placing same materials in one sheet. Like all types of wood goes in one texture sheet, concrete types in one etc. More like doing a very very effective mapping planning work.

Obscura

Yeah that would work fine with the slider. Also your texture library will be more organized then.

HAWK12HT

Aye but I am seeing black spaces then lol, not gonna be like those nice 0 wasted pixel texture sheets.

Obscura

I don't really understand this. You would go 0% wasteful only if you would use tiling textures. Also, padding can fill up a lot of unused space when its a "unique" texture.

EarthQuake

There is a numeric box/slider for metalness because some materials do not need a metalness map. If your texture is made entirely from metal, or contains no metal at all, you don't need a map. In that case you just need a 1 or a 0 value. You shouldn't tweak the metalness slider by eye, any changes should be made to the texture content.

Generally, metalness content should be either 0 (black) or 1 (white) in the texture content too, except for soft fades along transition points. Values other than 0 or 1 mean the material is partially metallic, which is extremely rare. Variation for metals would be created in the albedo map.

HAWK12HT

@Obscura I am talking about textuing like this

https://m1.behance.net/rendition/modules/159190845/disp/f0dad298e78f88b201a0c6224c37fdb9.png?cb=1212529878

HAWK12HT

@EarthQuake Thank you its getting clear more to me, though if its 0=nothing no metal then why is it I am seeing people using black texture in Unity in metalness slot. My guess is that if you want 0 value in metalness the default standard shader gives slider for smoothness which I think is fancy name for Gloss / Roughness in Unity, this smoothness option however disappear when you add just black texture. Also results are different too with black texture vs just 0 values both for metalness and smoothness.
Also by 0 metalness you mean its not metallic or matte metal?

EarthQuake

Smoothness in unity = gloss/roughness (how rough or smooth the surface is) in other engines. This shouldn't have anything to do with metalness or specular maps, which define reflectivity (how much light a surface reflects), but I'm not a unity export

0 metalness would mean the material is an insulator, its not made of metal. Metal with pant on top of it would be 0 metalness too, as you're defining the top layer. Painted metal with scratches that reveal the bare metal below would be 1 metal, but only at the scratches.

Obscura

@HAWK12HT - Okay, I would simply go with individual textures.Using atlas textures is not really necessary nowadays in my opinion, just on mobile platforms.

kio

in regards of unity:

in the standard shader metallness and roughness are packed into the same texture:

R - Metallic
G - not used
B - not used
A - Roughness

there is no way to just declare a roughness map and use a constant value(aka slider) for the metallness in the current workflow.

HAWK12HT

ahan cool, so paint gets black, scratch gets white in Alpha slot this is really helping guys. Thank you so much. Yes I am reading PBR stuff from Marmoset site and will check out Substance guides later.
So if paint is black in gloss how would you define its property O_o like matte paint or gloss paint or mettalic.
aye speaking of specularity there is one shader that says "specular setup" in Unity.