Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

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MrBlack
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Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

Post by MrBlack » Tue Jun 23, 2020 1:35 am

Hi simple question that may have been answered elsewhere but my searching hasnt found anything.

Which maps should we generate and where to plug them into Indigo

Indigos Phong Materials have the following maps inputs:

Colour
Spec Reflet
Roughness
Fresnel Scale
Bump
Normal
Displacement
Emission Mult


Poliigon for example will give you the following maps:

Color
Displace
AO
Gloss
Reflect
Metalness
Normal

My thinking in terms of with Poliigon would be
Poliigon -> Indigo

Color -> Colour
Metalness -> Spec Reflect
AO -> Not used
Gloss -> Fresnel Scale
Reflect -> Roughness
Normal -> Normal
Disp -> Disp



The really confusing part is the Fresnel Scale and the Roughness maps......im not 100% sure what to plug into there as whether I try putting in the Gloss or Reflect map I end up with a weird result...I dont even know if I should use one or both maps.



And when using a generator like ShaderMap It produces these maps:
Albedo
Diffuse
Metal
Specular
Rough
Gloss

This brings in even more confusion.
ShaderMap -> Indigo

Albedo - > Colour
Diffuse -> Colour?
Metal -> Spec Reflect?
Specular -> Spec Reflect?
Rough -> Roughness
Gloss -> Fresnel Scale?



Any help with the popular naming scheme conventions would be helpful.
The little hints that the UI gives arent really helpful as Im still lost.

Forgive me if this has been answered to death.

But I cant be the only one slightly confused, with the rise of more and more map generators a small tutorial or help guid for which maps are needed and where to plug them in would be really helpful.
If I can get this to work, ill probably produce the guide just so people know.

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thesquirell
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Re: Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

Post by thesquirell » Thu Jun 25, 2020 10:26 am

You know that IOR factor that you can control to increase or decrease the overall reflection of the surface? For example, when you put 20, it reflects all the light, making it a mirror like surface, but when you put 1 it just looks like that colour you specified, without any reflections? You can control that IOR factor across the surface with a map: That's the Fresnel map. Roughness map will determent the roughness of the surface. It may look confusing in the start because if you put a roughness value to 1 and have IOR 20, you will have the same surface as roughness 0 and IOR 1, but there is a difference between the roughness of the surface and the reflectance of that surface. So, if you want to add variability in the IOR factor itself, you would use a map in Fresnel scale. It doesn't have to be the same as roughness map, it could be your AO map, or Displacement map even. It's basically up to you, to art direct your surface! :D

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Re: Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

Post by pixie » Thu Jun 25, 2020 6:56 pm

just to add to the very good post from @thesquirell as far as metalness goes, would be through the use of a blend material with a metal map used as mask between a regular material(diffuse/phong) and a phong with specular reflection texture applied

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MrBlack
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Re: Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

Post by MrBlack » Thu Jun 25, 2020 8:44 pm

thesquirell wrote:
Thu Jun 25, 2020 10:26 am
You know that IOR factor that you can control to increase or decrease the overall reflection of the surface? For example, when you put 20, it reflects all the light, making it a mirror like surface, but when you put 1 it just looks like that colour you specified, without any reflections? You can control that IOR factor across the surface with a map: That's the Fresnel map. Roughness map will determent the roughness of the surface. It may look confusing in the start because if you put a roughness value to 1 and have IOR 20, you will have the same surface as roughness 0 and IOR 1, but there is a difference between the roughness of the surface and the reflectance of that surface. So, if you want to add variability in the IOR factor itself, you would use a map in Fresnel scale. It doesn't have to be the same as roughness map, it could be your AO map, or Displacement map even. It's basically up to you, to art direct your surface! :D
Thanks for the explanation.
Ill keep experimenting with shader generators to see if I can get similar results.
I never really used Indigo to do anything that was "advanced" all my renders are usually aiming for the very clean look.
pixie wrote:
Thu Jun 25, 2020 6:56 pm
just to add to the very good post from @thesquirell as far as metalness goes, would be through the use of a blend material with a metal map used as mask between a regular material(diffuse/phong) and a phong with specular reflection texture applied

Ahh this one was what was also confusing me......this actually makes alot of sense.
Its just in other engines this could be done with one material.
Second experiment.....damaged cabinet with exposed metal.

Thanks to you both.
Ill probably use this thread for my experiments going forward in case anyone else is as confused as I am Ill post results soonish.

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thesquirell
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Re: Fresnel Scale vs Roughness: Maps Generated from Substance/Shadermap/Mixer

Post by thesquirell » Fri Jun 26, 2020 2:03 am

Not a problem! Bear in mind that if you choose to use Fresnel map, the max value of IOR is the brightest pixel in your map (255), and the darkest (0) is the complete lack of reflectance. So, you can think of IOR value as the highest cap value, and grayscale map is everything in between. Speaking of which, it is a good practice, but not mandatory, to use linear colorspace for the greyscale maps, since it bears pure numerical information, without the need for correction, like a colour map would have (sRGB).

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