Where do I put a roughness map?
lorraineopua
Posts: 642
I import a lot of different models and most come with multiple maps. However, I'm flummoxed by the roughness maps. Where do I put them? Diffuse roughness or glossy roughness? At the mo I'm sticking them in both and hoping for the best.
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There is no One answer for all materials. Sometimes you might even find it in the Translucency weight. The best way that I figure out these questions is:
For skin - I load in a character preset and examine how the materials are set up
Similar ideas for other material types. Load in an example.
If you're using Iray, the most obvious place is Dual Lobe roughness, but you can use it for any sort of roughness (or any number of other functions).
That's a great idea, thank you.
It is for Iray but I can't find a Dual Lobe roughness...there is a Dual Lobe Specular Weight?
Trigger it >0, you'll see roughness for lobe 1 and 2 ~ You can just put the map into Dual Lobe Specular Reflectivity, that'll be fine~
For non-organic materials, I have had good results with the PBR roughness workflow putting roughness maps in both Glossy Reflectivity and Glossy Roughness and dialing them both up to 1. That seems to work with maps from Substance Painter. For skin and organic materials, I have played with the dual lobe channel as others have suggested here.
Thank you everyone for your help :)
im pretty sure the Glossy Group (Glossy Layered Weight, Glossy Reflectivity, Glossy Roughness) and the Specular Group (Dual Lobe Specular Weight, Specular Reflectivity, Specular Roughness) are two different ways of achieving the same thing - i.e., a gloss effect.
Dual Lobe Specular is the new and improved way of doing it, but typically only see it used for skin. I would think that the Dual Lobe Specular Reflectivity and Dual Lobe Specular Weight mapped channels probably wont accept a typical grayscale Roughness map and look the way the author of the roughness map intended though. So if you have a standard grayscale roughness map then probably dont use this as a specular map.
My two cents: if your maps are just for some basic PBR shader for like a chair or a brick wall or whatever, then just use the Roughness map in the Glossy Roughness channel, setting its value to 1.0, and make sure Glossy Layered Weight is not zero (probably setting it to 1.0 would be good if you intend to use this as your primary way of adding roughness/glossiness). Leave the Glossy Reflectivity at its default and dont change it (by default it is 0.5 if i recall). And leave Dual Lobe Weight at 0.
Note: you can create a gloss effect with various shader groups in iray uber shader
So in general, depending on how you are setting up the effect(1,2,3, or 4), the roughness map would go in the relevant slot for that set up.
Actually if you wanna use Dual Lobe, you better have different maps, e.g. specular map for reflection, two roughness maps for two lobes (e.g. one is sharp one is soft) ... If there‘s only one roughness map on hand, just using Glossy layer will be fine, no big difference. Or self-make some maps~
The reason why Dual Lobe is better for human skin is that all the channels on this layer can accept texture maps. Technically, different maps could be used in each channel for iRay engine to mix specular and scattering. It may bring you subtle change in terms of visual effects~ But practically, for most of the cases, it would be good enough while using 2 - 3 maps there...
you dont often see people putting roughness maps in the two daz iray uber Dual Lobe Specular roughness channels. I notice Daz PAs usually use those roughness maps for Glossy Roughness and Top Coat Roughness while putting no map in Dual Lobe Spec Roughness, but i guess it's up to the user to get the effect they want.
Nope, we don't often see, but there're quite a few for sure~ A couple of my friends are Daz PAs, we discuss such things from time to time. You may look at the characters from Goanna and VOOTW, for instance, though some settings there are still not that good. The mechanism is there, it depends on if you wanna use them and how to use them, incl. making proper texture maps for them. But still, maybe some PAs like to leave them to the users to get what they want by setting them properly...
to be fair, i have seen Daz PAs put roughness map in Glossy Roughness channel with Glossy Layered Weight set to 0.0, which basically means the map doesnt even do anything!
Lots of PAs did the same thing (turn off Glossy layer weight) while using Dual Lobes in iray Uber just because Glossy layer is above Lobes layer, it'll rune what you set on lobes. But it doesn't mean RH map will not work on Glossy layer. It's diff. thing~ Why there's no glossy layer in PBRskin shader? cuz you have lobes~~ which can well mix the specular and scattering on the skin ~~