Author Topic: Free Comprehensive PBR Guide  (Read 19407 times)

Hello,

The Comprehensive PBR Guide covers the theory of PBR as well as practical guidelines for application. It is divided into 2 volumes.

Volume One: The theory of physically-based shading and rendering

Volume Two: Practical guidelines and workflows for creating PBR textures.


Download the Free guide
http://www.allegorithmic.com/pbr-guide

Cheers,

Wes

Last Edit: January 29, 2015, 10:47:06 pm
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja

Thanks Wes, this looks like a great resource.

Awesome, thanks a lot Wes !

good work!  O.o

Huge and useful guide!
thank you  :)

Thank you so much Wes, keep up the good work :D

Wes, you are the man!
Away from home right now but I can't wait to get back and pour thru this. I've said this b4 and l'll say it again Allegorithmic is quickly becoming my favorite SW company! U guys rock!
THANK YOU

Nice you went down the scientific route for the tech heads.

A lot of the time I understand things 10 times quicker if I can see the general principle, and you gave that all here in a nutshell, thanks!

Thanks for turning these visual aspects of game building into something that is easy, OK, easier, to use.  It reminds me of the “First Reflections” used to build digital sound envelopes in signal processors, DSP's.  I’m glad for you, and me, that this digital game building environment has become so multifaceted and integrated that building the game can sometimes become more fun than playing the game, maybe, some days, if the AI tracks just right, where the music drives the pace and the lighting sustains the mood and my old wireless XBox 360 controllers work within the new Unity Web Player on my PC and and and … thanks for continuing to keep my plate full of even more light driven ideas and knowledge than I'll ever be able to chew, independently.
FarNiché,
An Indie Game Creator.

Thanks for the guide Wes. I have to say that it was the easiest to follow that I've seen. good job with that.

How far will these PBR methods go do you think? The new thickness maps look like a great addition, though I haven't had to use 1 yet, I know I will for sure.

I often wonder how different materials are effected by heat. What I mean is, there is the data available for common materials for example a lot of raw metals I assume in thier pure freshly cut state. But if you look at a metal that has been heat treated it can look quite different. In some cases where heating is uneven it can be banded in a multitude of different colours and properties.
Don't get me wrong I think PBR is great, but still the eye does not lie, and its up to the artist to replicate what it see's in at least some cases, yes?

That is unless some day a heat treated map is developed. :)
Last Edit: January 11, 2015, 10:19:11 am

Quote
Don't get me wrong I think PBR is great, but still the eye does not lie, and its up to the artist to replicate what it see's in at least some cases, yes?

Isn't this what we(artists) do anyway with scrapes, dents, dirt and grunge? :) The artist pushes the material passed it's base line existence, into a living state.

It seems especially so that metal seems to have really concrete characteristics. It's what "happens" to metal that totally changes it's appearance.

Quote
Don't get me wrong I think PBR is great, but still the eye does not lie, and its up to the artist to replicate what it see's in at least some cases, yes?

Isn't this what we(artists) do anyway with scrapes, dents, dirt and grunge? :) The artist pushes the material passed it's base line existence, into a living state.

It seems especially so that metal seems to have really concrete characteristics. It's what "happens" to metal that totally changes it's appearance.
Oh yes! absolutly. :)
 What I'm wondering, as far as being physically accurate, before we had thickness maps doing SSS details was done in a similar way to applying dirt and grunge. There's no data for every mix that these could be comprised of. I understand that's probably going to be always the case. A little hand waving to the realm of the physically accurate, so to speak.
 I don't know maybe these thickness maps have been around for while. They do seem clever and new to me though.
 Clever tool creaters are always comeing up with new ways to make things more realistic. I just wonder what will be next. Its not a question as such. I'm more stating that I'm in wonder of whats yet to come.
Last Edit: January 12, 2015, 06:27:41 am

Thanks everyone very much! I greatly appreciate the kind works : )


@SlowGain
"Don't get me wrong I think PBR is great, but still the eye does not lie, and its up to the artist to replicate what it see's in at least some cases, yes?"

This is a very good point. @TeotiGraphix posted a good explanation. Here is an excerpt from vol 2 where I begin to discuss this aspect as well.   

In PBR, the shader handles the heaving physics lifting through Energy Conservation and BRDF while we as artists, create maps that are guided by physics principles. It takes out the guesswork of material values and allows us, as artists, to spend more time in the creative aspects of texturing. While it is important to adhere to guidelines and author maps correctly, it doesn't mean that we now have to disregard our artist intuition. In fact, it’s the artistic perspective that truly brings character to a material, revealing its story through carefully crafted detail and expression. It’s important not too get overly caught up in the physics. Just because we are working in a more physically accurate environment doesn't mean that we can't do stylized art as well. For example, Disney's physically based reflectance model was designed to be a "principled" approach meaning that it was geared more towards art direction rather than a strictly physical model. So we should know the principles and utilize the guidelines, but not be slaves to them.

Cheers,

Wes
Integrations Product Manager / Training
wes.mcdermott@allegorithmic.com
Twitter: The3DNinja

First of all, thank you a lot for this guide, it is concise and has very good explanations and image examples.

However, I've got some doubts regarding the differences between the spec/gloss and the roughness/metal approaches when mapping reflectance.

As far as I understood, in the spec/gloss workflow, for a metal material you will paint it black on the base color map, and the corresponding F0 color value for that metal on the specular map. But, in a roughness/metal workflow, how should it be done? I guess you'll just apply white on the metal map (because it's metal), and paint the corresponding F0 color on the base color map, right?

Now, when dealing with non-metals, in spec/gloss you'll paint the diffuse color on the base color map, and the F0 value on the specular map. But in roughness/metal workflow? I thought you were supposed to just apply a base color and set the metal map to black... but then where is the F0 value applied? Can you apply it to the metal map instead of setting it to full black? apply an additional specular map with the F0 value (I think UE4 lets you do this)?

Sorry if next volume is planned to clarify this with more examples.

With non-metals the F0 value is very small and does not vary a lot between materials (except maybe for gems). The intensity of the specular reflection for non-metals is usually better changed by setting the roughness accordingly. As a consequence, in earlier implementations of the metal/roughness workflow, there was no way to change the F0 value for non metals and it was set to a constant (usually 0.04). Now some implementation also use a grayscale "specular" map to specify the F0 value for dielectrics. In Designer it corresponds to the usage "SpecularLevel". It maps linearly F0 values from 0 (black) to 0.08 (white), the default value being 0.04 (mid-grey).
Again, in practice the roughness map will make much more visual difference, and most existing non-metallic materials have an F0 value very close to the default.
Last Edit: January 13, 2015, 02:15:57 pm