Tutorial - PBR and Metals Technics

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(Renatoaruffo) #1

Hello everybody,

my name is Renato, I am a character design, game designer and owner of a small Brazillian company called Nuclear Scorpions.

I see a lot of people with some problems when creating metals. Metals are very tricky some times, but when you get it it becomes one of the coolest and most pleasure stuffs to create.

With PBR shaders on the market we can get some really cool good looking metals around there, and here I am giving some tips, inside you can double click on the numbers and see some infos. Here is a small demo scene:

Tutorial - PBR and Metals Technics by renatoaruffo on Sketchfab

Metals:

Pure metals has no diffuse on it, all it colors comes from the reflection, this is how our physical world works, and it is going to be exactly how you can give a cool look on a PBR shader.

Each render or engine may work a little different on the sliders, but the results are always be the same.

Diffuse color - The diffuse color is basically the color over the surface of the model, there is not much secret on it.

Metalness - Metalness is the trick here, how does it works? It simply creates a specularity based on the diffuse color, so if you put it on the highest value and have a black diffuse, it will not work. If you put a cool gold color on the diffuse, it will generate a golden specularity on it. That is the secret while using Metalness. At the time that I didn't know how to use it, I randomly picked some number until reach some cool results.

Specular color- In the PBR, specularity is the reflection on the surface. It is going to be blurred and affected by the Roughness/Glossness

In a non-physical shader, reflection and that specular shining ball on the surface are separated. A blinn for example.

Roughness/Glossness - This is the magic of metals, if you make a cool roughness/glossness map you will have a nice metal. This basically creates a disturbed surface that simulate the light/reflections hitting the surface and bouncing in a irregular way (making that blurry).

The difference between Roughness and Glossness are the values, they are inverted.

On Roughness the black areas are the most shinning, on glossness, the white parts are.

You just have to know which one the program you work on uses. Unity 3D, for an example, uses glossness, while Unreal 4 uses roughness.

If you need a gloss on a roughness engine, you just open the texture and invert the colors, simple as that.

Hope you enjoyed it and that it helps you all.

Best regards everybody smile


Aluminium Material
Artist Picks: Chaitanya Krishnan (chaitanyak)
(Simon Kratz) #2

Nice explanation and good example there smile
Here's a little contribution from my side: Some resources with pretty useful information and calibration profiles for various materials:
forum.unity3d.com/threads/official-5-0-pbr-calibration-charts.289416/ - Unity's calibration sheet along with downloadable scene smile

allegorithmic.com/pbr-guide - More of a guide for theory behind PBR but also contains some calibration values for different materials. A lot to read, but really good.

docs.google.com/document/d/1Fb9_KgCo0noxROKN4iT8ntTbx913e-t4Wc2nMRWPzNk - Shared google doc by a member of the polycount community; check "Material Reference Values" for the calibration values, but the whole thing is worth reading.

And a final link for PBR theory along with texture conversion to get best pbr results by the awesome guys of Marmoset:
marmoset.co/toolbag/learn

Recently shared this stuff in a comment after someone asked me for my workflow when defining materials.
Hope others are profiting from this as well wink


(Stevenb) #3

I have seen this information before somewhere I think stuck_out_tongue . Very useful. Thanks to both of you!


(Renatoaruffo) #4

Yeah.. amazing information, thanks for sharing, there are lots of information behind the PBR. These links and pdfs are amazing amount of details behind it and the more you know better results you get.

My suggestion is to learn and read these articles, makes lots of tests, try unity, unreal, metal ray, vray, understand how it works and what is the difference and similarity between these tools. It is a study that will rise the quality of the work in a gorgeous way, also almost everything is physically based today.

Thanks guys.


(Adeboye Grillo) #5

Thank you for the very simplified and easy to understand tutorial.

The PBR method really has a lot of freedom. The Metalness Workflow makes it easier to render metals even though you can still achieve realistic looking metals with the Specularity Workflow provided that you have all the necessary maps (emission, ambient oclussion, cavity, normal/bump and specular maps).

The fresnel 0 map slot is used (when metalness is set to 0) to specify how shiny non metal materials like plastics will look.

The idea is just to express yourself and create the necessary impression to convince the observing eye.

Thanks


(Renatoaruffo) #6

Yeah, I am really glad that you guys enjoyed it smile

I made a few materials, with some models I had here, using all this concept. You guys can download it if you want.

Medieval Weapons by renatoaruffo on Sketchfab

There are lots of details that are not covered in here, I tried to make something really simplified and fast for understanding it. If you guys want I can make a few more tutorials about this and other stuffs, it will be a big pleasure to help.

Bests everybody smile


(Shaderbytes) #7

Cool to explain simple details to everyone. I have some different preferences for Gold, so to add to your example I created 4 gold samples with the color for each in the annotations. Firstly I like it to be more rough , I'm using 15 for the value and a few different colors ranging from yellow gold to orange gold to red gold to white gold.

Gold Material Examples by shaderbytes on Sketchfab


(Simon Kratz) #8

Wow these are some beautiful definitions shaderbytes! open_mouth
Definitely gonna try thwese settings, theyre great! blush


(Renatoaruffo) #9

Yeah, that are really cool variations for gold.

Gold are very reflective, but there are many different ways that people uses gold, there are more polished gold, so depending on the style you are doing you can increase or decrease the roughness.

I personally love to make a rough gold, like you did, love the final result smiley The diffuses are also great.


(Shaderbytes) #10

Thanks essimoon ad renatoaruffo

Yes roughness can vary of coarse depending on tarnish or polished feel required. My colors are from my recent experiments when working on a gold piece in the last Unity competition. I looked at many different images and found these variations. Wikipedia has a page on colored gold :

I just experimented within the realms of this knowledge , so red gold does look similar to copper .. because it has copper mixed in it wink My white gold is probably still too tinted more like what they call rose gold. Anyway its great to bounce info and interpretations of each other and build up a collected knowledge wink

here is the Gold piece I worked on :

Ark of the Covenant by shaderbytes on Sketchfab


(Renatoaruffo) #11

yeah.. that is awesome. Nice work. It was a unity 5 competition with their new PBR??

I love unity engine. For me, it is the best engine at the moment.


(Adeboye Grillo) #12

I love that piece. Ark of the covenant. I love it so much. Thumbs up.


(Veyratom) #13

Thank you renatoaruffo ! This is very interesting. I have now a better understanding of metallic PBR shaders.

I will try to improve this scene :

Cyberchess set by Veyratom on Sketchfab


(Simon Kratz) #14

Something for reference with @shaderbytes values at use:
Just uploaded an old project of mine and reworked the metallic textures according to your values,@shaderbytes.
Pretty satisfied with it, your settings definitely rock! smiley

Armored Dwarf Bust by essimoon on Sketchfab


(Shaderbytes) #15

WOW @essimoon The armor normal map was the last image to load in the viewer for me , It's awesome! that is some pretty intricate detailing :wink: Did you do it via high to low bake down , or paint the mapping with detailed brush masks?


(Simon Kratz) #16

Thanks @shaderbytes, glad you like it smiley
I did the traditional high poly to low poly bake workflow^^ It lost some if it's quality during the bake but can't help it I guess. Still pretty happy with how he turned out.