Creating PBR Materials from Image Set

[BigAl3D]

I've got most of this down, but there are certain channels that seem better suited for a nodal material system. Since there is still time for Corona to have nodes, what is the best channels to use all of the images that come with PBR sets? Below is an example of a set I downloaded. Thanks.

Tiles 3_Alb.jpg  —  Diffuse?
Tiles 3_AO.jpg  —  Not Sure
Tiles 3_Dif.jpg  —  Diffuse?
Tiles 3_Dis.jpg  — Displacement Channel
Tiles 3_Nor.jpg — Bump channel with Corona Normal
Tiles 3_Ref.jpg  —  Reflection channel
Tiles 3_Rou.jpg  —  Reflection channel?

[Cinemike]

I've got most of this down, but there are certain channels that seem better suited for a nodal material system. Since there is still time for Corona to have nodes, what is the best channels to use all of the images that come with PBR sets? Below is an example of a set I downloaded. Thanks.

Tiles 3_Alb.jpg  —  Diffuse?
Tiles 3_AO.jpg  —  Not Sure
Tiles 3_Dif.jpg  —  Diffuse?
Tiles 3_Dis.jpg  — Displacement Channel
Tiles 3_Nor.jpg — Bump channel with Corona Normal
Tiles 3_Ref.jpg  —  Reflection channel
Tiles 3_Rou.jpg  —  Reflection channel?

Interesting challenge.
Alb(edo) is usually for the Diffuse channel. You can multiply (in a layer shader) the AO texture with it to get more or less variation.
Rou(ghness) goes into Glossiness (Reflection channel), but needs to be inverted (Filter shader or in the texture itself in the shader tab set black point to 1 and white point to 0).
Dif.jpg - no idea, could be used as diffuse texture probably if Albedo is not what it should be, one would have to see it.

Contrary to what everybody else thinks I still believe that such materials (with a set of one purpose textures) are set up more quickly without nodes.

[BigAl3D]

Yeah, before Corona I got Cycles4D. Their node system is amazing, but for me, very slow compared to Corona. Anyway it was easy to set up, but then again, it is a finished shipping product.

One more question, I did notice that I had to invert certain maps. Is this true for all non-color maps in a Corona material?

[Cinemike]

I only had to invert roughness maps so far.

[BigAl3D]

Another question. When using a reflection map, should it go in the Color Channel or the Fresnel IOR channel?

[Eddoron]

I've got most of this down, but there are certain channels that seem better suited for a nodal material system. Since there is still time for Corona to have nodes, what is the best channels to use all of the images that come with PBR sets? Below is an example of a set I downloaded. Thanks.

Tiles 3_Alb.jpg  —  Diffuse
Tiles 3_AO.jpg  —  optional mix to be multiplied with diffuse
Tiles 3_Dif.jpg  —  Diffuse
Tiles 3_Dis.jpg  — Displacement Channel
Tiles 3_Nor.jpg — Bump channel with Corona Normal(check Y alignment)
Tiles 3_Ref.jpg  —  Reflection channel(color)
Tiles 3_Rou.jpg  —  Reflection channel(gloss, invert map)

[BigAl3D]

Let me clarity, does it go in the Color Channel of the REFLECTION tab, or the Fresnel IOR? There are five slots for textures. Thanks.

[Cinemike]

Let me clarity, does it go in the Color Channel of the REFLECTION tab, or the Fresnel IOR? There are five slots for textures. Thanks.

I only use the IOR texture slot when I have a material that needs different IORs.
Example: Painted metal, where scratches and bare areas show through.

[PROH]

Ideally reflection should be set to 1 and reflection color should be set to pure white (with no reflection maps used), unless it's a metal where albedo/diffuse is set to zero and the color is derived from the reflection color.

Hope it helps

[Eddoron]

Ideally, reflection should be set to 1 and reflection color should be set to pure white (with no reflection maps used), unless it's a metal where albedo/diffuse is set to zero and the color is derived from the reflection color.

Hope it helps

Without a reflection map, you might have dusty/dirty spots or dark cavities just as glossy as other parts. If you're unlucky and there's no gloss/rough. map provided, it will look terrible. Softening and adjusting the AO map can help in both spec and gloss maps missing.

Let me clarity, does it go in the Color Channel of the REFLECTION tab, or the Fresnel IOR? There are five slots for textures. Thanks.

I usually connect my reflection/specular map to the reflection weight. The highlight intensity is then quite easy to change. In Coronas case, this would be the "level" but that currently does not allow maps. So put it into the reflection slot at the top.
The IOR slot is only used when you have a material with different IORs like mossy-rock (inorganic  or artificial things mixed with organic, layers of metal or paint etc.)

[Nejc Kilar]

Ideally, reflection should be set to 1 and reflection color should be set to pure white (with no reflection maps used), unless it's a metal where albedo/diffuse is set to zero and the color is derived from the reflection color.

Hope it helps

I wanna chime in here :)

With the new PBR "OKed" materials and the ability to tone down the glossiness to 0 you can actually get away with not using a reflection map but instead just a glossiness map.

It totally depends on how good it is but essentially the idea behind it is that if there is a non reflective part in your glossiness texture then it will be represented by a pure black value. That in turn means glossiness is at 0 there and so the reflection will be diffuse rather than... Well... A reflection.

"Diffuse" is still a reflection of sorts but its just really, really "blurry". From my understanding for most rendering engines its usually just easier to calculate a solid color and not bother with calculating extremely diffuse reflective surfaces. The end result is pretty much the same anyway.

For me personally, in practice, I tend to still use reflection maps. It just gives me extra control over the spots where I want to adjust the strength of the reflections.

[PROH]

@Eddoron: I wasn't talking about a situation where no glossiness map exist (in this case an inverted roughness map). As nkilar explain, this is the physically "correct" PBR method with Corona (but artistically you can of course do whatever you want to get the desired look).

In some of Dubcats threads, this is discused intensively - check them out. In those threads Dubcat shows how reflection maps in Corona actually messes with the reflection IOR, and he even provides a spreadsheet to calculate this.

Hope it helps