How do you guys create Roughness maps for PBR? Any examples? Also a few questions.

ahendowski

I've seen a few examples, such as the Cerebus textures:

http://www.polycount.com/forum/showpost.php?p=2003489&postcount=19

and the ones from the marmoset website:

http://www.marmoset.co/wp-content/uploads/lenstextures01.jpg

One of my questions is, how do you guys go about creating roughness maps? Any certain techniques you guys try? Any tips? I'm almost done with figuring out this PBR stuff, and I'm really excited to get working. I'm running a ton of tests on different materials but am dying trying to create these certain things.

Also, as far as the albedo, is it now more logical to kind of paint in the albedo?

I've seen in the marmoset example, his normal maps are REALLY clean, without much bumps in the design itself where the plastic is, and I see that's more taken care of in the roughness map. Is that the better way to do it now?

tl;dr:

1.) How do you guys go about roughness maps? Any tips?
2.) Albedo maps, are they solid color now, and is it better to paint in the color of the metal and let roughness define how it is?
3.) How important are normal maps in terms of creating bumps in plastic and whatnot? Are normal maps more considered to show different details such as letter imprints and things of that like, or are we still creating roughness from normal maps?

Thanks everyone!! It's been very fun learning all this PBR stuff and I really want to excel in it and completely learn it, and then maybe give back to the community once I understand it fully!

EarthQuake

1.) Use reference, observation, and general logic. Roughness does exactly what it sounds like, defines how rough a surface is. This will vary by a wide number of different factors like the material type, wear level, etc. There is no secret here, you just need to research and experiment.

2.) The albedo is the color of the material, without any lighting or anything else. If you're using a metalness map, its also the specular color/intensity of the metal parts. Not sure what you mean by "kind of paint in the albedo". How flat or detailed the albedo will be depends highly on the surface type, for something like concrete you will have a lot of detail in the albedo, for glossy clean plastic, much less.

3.) It really depends, for larger detail, like the leather grip on a camera or grip pattern on a gun, you generally going to want to do that in the normal map. For very very fine detail, you generally don't have enough resolution to represent it in the normal map, so do it in the gloss/roughness.

Mark Dygert

Correct me if I'm wrong but doesn't roughness just refer to "micro surface detail"?

No real surface is completely smooth. Use roughness maps to simulate microscopic natural irregularities.

3. Use spec and roughness maps to simulate surface irregularities
In real life, even the smoothest of surfaces – be it a car paint or a mirror – will exhibit variations in the way it reflects light. Things like fingerprints, the direction in which the surface was wiped and slight fluctuations in the coating will cause surface irregularities that can be simulated with roughness maps.

Similarly, bear in mind that objects don’t always reflect the same amount of light in every direction. For example, when dirt accumulates in creases on a surface, it reduces their reflectivity. This phenomenon can be reproduced with spec maps. Variations in spec maps is the key to creating truly photorealistic materials.

Taken from HERE.

Roughness won't handle anything major like creases, wrinkles, dents, screws, divots or rivets, that's what the normal map is for. It's kind of like an "additional bump" if you ever used one of those.

Or is there more to it? I haven't dug too deep into this new material creation stuff but it seems like they are just syncing up with regular CG techniques?

stevston89

I thought roughness was just a control on the specular spread. Very similar to a gloss map. There is no need to over complicate it. Yes a more rough surface will have more little divets/ bumps causing the specular highlight to spread out, but all you need to worry about is controlling where the spread happens and to what degree.

passerby

@stevston89 it is also engery conserving so you no longer control the spread separate from the intensity. Acts like real life now, the same amount of light hitting a object always reflects back. It just does it in one tight and bright highlight, or in a more broud and dim highlight.

Also it is inverted, 1 is very rough, and 0 is a mirror surface, vs gloss used above 1 vvalues, where higher numbers tightened the highlight.

Also roughness controls what blurred mipmap is used for the cubemap, and I do belive it controls something similar to the diffuse power of the old Lambert system, and Fresnel.

stevston89

passerby wrote: »

Also it is inverted, 1 is very rough, and 0 is a mirror surface, vs gloss used above 1 vvalues, where higher numbers tightened the highlight.

This depends on the engine. Marmoset doesn't have the values inverted like UE4 does ( though you can invert them). The overall gist though is it isn't that much different from how you made maps before with spec/ gloss workflow. You need to use observation as EQ said to figure out roughness/ gloss of a material.

passerby

Ya more or less the same but 1 map controls the intensity, spread, and that the albedio contains little to no fake lighting now, no cavity or ao

3dlix

Hey check out this video : https://www.youtube.com/watch?v=AvOQYUjAw_Q - Physical based Rendering - A practical Workflow for 3D Artists- Featuring Substance painter.