Physically Based Texturing Breakdown
Hey guys, I'm learning the new PBR texturing process and am getting to know and create the new maps. I've looked over a lot of forums and helpful advice from sites, some good reads I found on PBR are
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/PhysicallyBased/index.html
http://www.artisaverb.info/PBT.html
http://www.marmoset.co/toolbag/learn/pbr-practice
After going through all of the reads and studies, its still kind of hard to wrap my head around creating the new materials. From my understanding this is how my brain begins to think about the following textures used to create a PBR Material. I'm currently using UE4, which takes use of the Albedo (Base Color), Metallic (spec), Roughness (Gloss), and Normal maps.
Albedo - When I create this map I usually just create it as a diffuse without the shadows from the AO map. Basically just no multiplied AO over top of all my layers. No highlights on any of the source textures, if I have any I usually just paint them out. Aside from all that I still kind of feel as if my Albedo texture is lacking something.
Metallic - For the most part I feel as if I understand metallic, I've been treating it as if all wood or rubber textures be painted black and anything that is metal should be white and transitions be a grey color. If I'm missing something here please fill me in.
Roughness - The roughness map is hard for me to wrap my head around because this is where the artist can really let loose and show some creativity. Looking at examples from other artists and reading about it, it seems as if the roughness map can be anything you want really, it's like a gloss map with more detail showing areas on your asset that have wear on them. In UE4 Does the whites display more roughness or is it the black?
Excuse the uneducated rant on PBR, just trying to get a grasp of the new workflow for my environment in UE4, any comments or help on the subject would be mass appreciated, thanks all.
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/PhysicallyBased/index.html
http://www.artisaverb.info/PBT.html
http://www.marmoset.co/toolbag/learn/pbr-practice
After going through all of the reads and studies, its still kind of hard to wrap my head around creating the new materials. From my understanding this is how my brain begins to think about the following textures used to create a PBR Material. I'm currently using UE4, which takes use of the Albedo (Base Color), Metallic (spec), Roughness (Gloss), and Normal maps.
Albedo - When I create this map I usually just create it as a diffuse without the shadows from the AO map. Basically just no multiplied AO over top of all my layers. No highlights on any of the source textures, if I have any I usually just paint them out. Aside from all that I still kind of feel as if my Albedo texture is lacking something.
Metallic - For the most part I feel as if I understand metallic, I've been treating it as if all wood or rubber textures be painted black and anything that is metal should be white and transitions be a grey color. If I'm missing something here please fill me in.
Roughness - The roughness map is hard for me to wrap my head around because this is where the artist can really let loose and show some creativity. Looking at examples from other artists and reading about it, it seems as if the roughness map can be anything you want really, it's like a gloss map with more detail showing areas on your asset that have wear on them. In UE4 Does the whites display more roughness or is it the black?
Excuse the uneducated rant on PBR, just trying to get a grasp of the new workflow for my environment in UE4, any comments or help on the subject would be mass appreciated, thanks all.
Replies
The ones you linked are not very complete or have some holes/inconsistencies.
That said, what you'd grasped from it so far all sounds correct.
Now with PBR it makes way more sense: glossines (or roughness or microsurface) has the details you'd have in specular, like smudges, material separations from sharp mirror-like all the way to matte. Instead of only affecting specular highlights like in last-gen, it affects blurrines of actual reflections.
And specular (or reflection) is straight-forward, it can be grayscale or colored. Metalness (from my understanding) determines if the value for reflection is chosen from the diffuse (if you have a copper sheet your specular needs to be copper-color, as in the diffuse) or assigned a standard value.
So if metallic unreal uses a black albedo behind the scenes and uses the albedo input as reflectance. Than with metallic false, it uses a hard coded reflectance and albedo is albedo.