Why the big fuzz about PBR?
greentooth
So i was wondering why everyone is trying to make such a big thing out of PBR.
Because if you look at it from an artist perspective and ignore the underlying math for a moment the only thing that changes compared to traditional rendering is that the glossmap now also has an influence on the specular strenght.
Now the reason why this is weirding me out is that a lot of artists seem or seemed to struggle with PBR at first, when realy not much changed in terms of workflow.
Not helping are those new terms for texture-maps wich basicly convey the same meaning and seem to serve only to confuse people.
Do we realy need to call the Diffuse, Albedo now? Glossiness.. Roughness wtf.
Hell if you don't have AO maps due to memory constraints for example, you still need to bake your AO into your diffuse and spec maps.
Do you guys feel the same, or am i totally misunderstanding something?
Because if you look at it from an artist perspective and ignore the underlying math for a moment the only thing that changes compared to traditional rendering is that the glossmap now also has an influence on the specular strenght.
Now the reason why this is weirding me out is that a lot of artists seem or seemed to struggle with PBR at first, when realy not much changed in terms of workflow.
Not helping are those new terms for texture-maps wich basicly convey the same meaning and seem to serve only to confuse people.
Do we realy need to call the Diffuse, Albedo now? Glossiness.. Roughness wtf.
Hell if you don't have AO maps due to memory constraints for example, you still need to bake your AO into your diffuse and spec maps.
Do you guys feel the same, or am i totally misunderstanding something?
Replies
I just started texturing my characters this year.
First I only used Diffuse and Normal maps.
Then I learned to make Spec and Gloss maps as well. (with spec in color instead of black&white depending on what color it reflects)
And.... that's kinda where I am at now. Is that like... what... half PBR ? the Old PBR ? I have not a clue.
Metalness ? Roughness ?
I'm lost.
For why it is confusing is because many things changed from traditional workflow. For example, you have to choose between Metalness and Specular workflow, which are two different things. There's now an energy preservation system, there's color in your specular or color in albedo that feeds specular if you choose Metalness approach. Now you have to gather different science-based specular values for metals to use them, which eliminates a guessing work at least on the basic level, but also provides its own set of challenge when you can't find values for an exotic material.
Changed the way you think about textures. It's all more logical now and relies less on chance. It's easier to reuse materials, because they will look good under any lighting conditions.
As to why new names for old maps. Well, partly because of how different the new workflow is. Helps differentiate between old and new and adapt to this new approach that requires a different thinking. I'm sure someone else can answer that in more detail.
You claim that not much changed, but clearly do not understand it fully yourself...
PBR is a more basic approach to describe a material than the old way.
Also there is no longer a separation between specular highlights and 'cubemap reflections'; it's all reflections and a good engine treats them all equal.
In fact, it's easier, as you just need to stick to some basic rules, and your assets will look good in any lighting condition. I remember in Crysis 3 you had to do a lot of hacks to make stuff look good in direct sunlight vs. shadow, especially metals. In Ryse and SDK 3.6, you just stick to the recommended values and assets will look fine no matter where.
It's important to resist the temptation to add AO/Cavity to the diffuse, though. It's super tempting at a stage where the levels are still empty, lighting is still bad, etc, and you don't want to be the guy checking in flat-looking boring textures. But once someone starts, it becomes a bit of an arms race to make things "pop", and the end result of the game will be a noisy, unreadable and overly busy looking mess.
For a normal diffuse looking material there is not much differense in the pipeline or even outcome. But previously complicated materials like metal, gold, water and glass is way easier to make with pbr.
Ofcourse if you make mobilegames or old school handpainted stuff you wont notice much of any difference.
Pbr really has changed thingd. Esp if you are making actual games and not just portfolio pieces. The way you handle texturing in gameengines are very different and much more effective.
there is def change if you are working in an engine making games.
Not that much when making portfolio pieces.
There is a lot more to pbr then the texture maps alone. And no. Not much differense if you are making handpainted or mobile stuff.
Well Ive noticed a few more changes in workflow than what youve mentioned but its not a big deal really.
1. much much less lighting in albedo (none if possible) so avoiding AO and gradients etc for realistic work, where before those were common for some people
2. albedo can dictate specular/reflective colour of metal in some pbr shader models right?
3. roughness map now controls a lot of the materials look and feel and contains almost all the little details that people used to put in thier albedo and specular
If you were already used to authoring textures with diffuse, normal, specular and gloss then its just a few small adjustments.
As for why they chose to call it Albedo specifically; just to be douches, I would imagine. The name has nothing to do with what the map actually does. I imagine it was just a situation like "Hey, what's another name for light reflection? It all has to reference light reflection, because PBR is all about LIGHT REFLECTION!"
http://en.wikipedia.org/wiki/Albedo
Nope. Roughness and gloss both define the micro-surface of a material, both do exactly the same thing, but roughness usually (but not always) uses an inverted scale where white = most rough and black = most glossy.
The reason some switched to roughness vs gloss, even though they do exactly the same thing, is to some people glossiness is used interchangeable with shininess or reflectivity, which can be confusing, so some feel roughness is a more descriptive or appropriate word.
Specular power and specular exponent are also interchangeable terms for gloss/roughness, depending on which app you use.
Albedo is simply a more technically accurate description of what the map does these days. Albedo in this context means "base color", while diffuse refers specifically to diffused light. This is an important differentiation to make especially when working with the metalness workflow as pure metals typically have no diffusion, so the albedo map works as both the diffuse and specular map for non metals and metals respectively.
There are some more misconceptions here, but I don't have the time to respond to everyone in this thread. I would recommend reading the following:
http://www.marmoset.co/toolbag/learn/pbr-theory
http://www.marmoset.co/toolbag/learn/pbr-practice
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/PhysicallyBased/index.html
Right, you still need to understand art fundamentals and especially material properties to make PBR textures.
While PBR doesn't automatically make your textures better or anything like that, if you're following the basic PBR guidelines and using logical material values, your art content is going to work more effortlessly in a variety of different lighting conditions, which was generally not the case with previous workflows. Consistency in art content creation is a huge part of the whole PBR thing. Though much of the concepts in relation to consistency are things some of the more organized studios were doing before PBR was a buzzword, I imagine like all the stuff you guys do with your automated pipeline.
The first thing to understand is that everything, literally everything you see in the world around you, you see because of reflected light. You can't see an object that doesn't reflect light.
Albedo is a measurement of reflected light. Diffusion is a specific type of reflected light (indirect reflection, which gives non-metal objects their base color). Diffusion happens because the light penetrates into the surface of the material and bounces around and then back out at random (but uniform) directions.
Objects appear a certain color because of how different materials reflect different wavelengths of light. EG, if a material reflects or absorbs the red spectrum. Sub-surface scattering can be explained in similar terms, SSS color is determined by how far different wavelengths of light penetrate a surface.
Specular reflections on the other hand hit the surface and bounce directly off like a mirror, this is why specular is a view dependent effect. For non metals, specular reflections are rather low in intensity (around 2-8% typically) and usually evenly reflected through the color spectrum (so, white or colorless). Pure metals reflect most of the light that hits them while absorbing none of the light, so the color that you see comes from specular reflections only. Why certain metals have different colors is because again, they reflect different wavelengths at different intensities.
If you want to get more technical, for non-metals its diffuse albedo and for pure metals its reflectivity albedo.
Again, with the metalness workflow, your albedo map defines both your diffuse and specular values depending on the material type. Here it makes no sense to call it a diffuse map, because its not a diffuse map. Though the metalness workflow is NOT required or mutually exclusive to PBR.
If you're using a full color specular intensity map its reasonable to call the base color map a diffuse map as it will only define diffused light.
Though there are certain preconceived notions of what a diffuse map is and what it should contain, like direction lighting, ao, cavity maps, etc that generally shouldn't be there in a PBR workflow, which I think was also a motivating factor in switching to a different term.
However, color is light, so they sort of did say something about color. Simplified explanation: A red apple isn't technically red, it just reflects red light and absorbs everything else.
Albedo is a measurement of diffuse reflectivity, so it's effectively just looking at which colors of light are reflected (the colors you see on an object) and which are absorbed (the colors that an object is not). Also, silver and gold is a bad example, because metals are different physically, which is why "metalness" is a thing. The differences for metals and iridescent materials are more complicated and I don't have time at the moment, but if people are interested I can tackle that a bit later.
If anyone wants a more scientific/less simplified version of that, let me know. Also, if that doesn't help clear it up, tell me that too and I'll give it another go.
If it is a specific type of Albedo that refers to color though, then I guess that explains why none of those links seemed to reference it.
2. More predictable results
3. Standards are always a good thing (even if there's multiple variations of that standard)
4. No need to add cube maps and fresnel to everything and manually adjust it.
5. With metalness, you don't need a color specular, so you can actually save memory.
6. Realistic materials/lighting is always a good thing, there's a reason why even Pixar uses PBR.
So it makes our jobs faster and easier, is there a reason why we shouldn't be excited for it and use it? (Besides our engines not supporting it).
People who were already confused and texturing D/S/G maps with bizarre data had the hardest time adapting. This was most of the fuzz.
But on other hand most of other materials, which are fairly rough, it doesn't change much.
In case of pure metal you can always check roughness value for it and set it.
In case of something like brick wall mixed with concrete, creating something like roughness map end up being guess work and just making it look good. (read, there is enough variation to make it look interesting).
/discuss.
edit:
Something else. How many of you seen adamantium ? Oh there goes you reflectivity chart
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