Cinema 4D's PBR Materials for Dummies!

One Dyslexic man's fight against
the PBR Workflow.

I can get my head around most things, but C4D's PBR materials have had me scratching my head on more than one occasion. Yes I am dyslexic and yes it took me more than a few tries to pass my maths and English exams, but it can't be that hard? Can it?

Having said that I spent the best part of today trying to get my head around these materials, their settings and what they do. So if you like things spelled out really simply, why don't you join me on this journey into the world of PBR materials in C4D. Who knows, we both might learn something!

 
 Why you so simple but confusing?

Why you so simple but confusing?

 

Fair warning, this is going to be pretty basic stuff.

If you're anything like me you like to know “why” and not just “how, so in this post (and maybe a few others) I'm going to break down everything I'm learning step by step so that I and hopefully you, can really see what's going on in this mysterious shader.
Today I'm going to take a simple look at what happens when you load a black and white image into some of the reflection channel's err... channels.

Looking at the basics:

Let's look at what a single black and white texture does in the different channels.

Blog_Image_001.jpg

So fig. 1 is my base object, a cube with Cinema 4D's PBR material applied to it. Lambertian (Diffuse) with reflection and specular at 100%. Simple!   Fig. 2 is the diffuse channel with the default Reflection channel on top. Beckmann, with the Roughness set to 20%, the IOR (index of refraction) set to 6, everything else is set to 100%.   Fig. 3 is the texture I'm going to use to drive all the different channels.

Blog_Image_002.jpg

OK so Fig. 4 is the black and white texture in the "Roughness" channel. We can see that where the texture is white we get the full 20% roughness and where the texture is black it pushes the roughness back down to 0%. Good to know. See we're learning something already!
In fig. 5 the texture is only in the "Reflection Strength" channel. This time the white is letting us see 100% of the reflection and the black is taking it all out, leaving us with no reflection at all.
Fig. 6 is the result of both channels being combined. We can see that the channels are starting to mix and giving us a more interesting look. This would be enhanced if the textures were different. (i.e. black and white in different places duh!).

So in the Roughness and Reflection channels black hides and white revels. It's kinda like shining a torch around. You shine the light where you want to see and everything else fades in to the darkness. I know that might sound childish and simple but writing it out like that helps me remember the rule.

Blog_Image_003.jpg

In fig. 7 I turned all that off and just applied the texture to the "bump" channel. Here we can see that the white is pushing everything out and the black is driving everything back. Fig. 8 is the same thing but with the "Displacement" channel. Again we can see that white is pulling the geometry out and the black is pushing it in. Fig. 9 is that one black and white texture from
fig. 3 driving the Roughness, Reflection strength, bump and Displacement all at the same time.

 
 Ohhh 3D!

Ohhh 3D!

 

Summary.

So in the "Roughness" and "Reflection Strength" channels, I said that a light texture makes things visible and a dark texture keeps things hidden. Haha, I told you a torch was a good analogy! In the "bump" and "Displacement" channel's white pushes things out and black pull them back. I'm going to think of this as a mountain. You know white snow on top and deep dark valleys down below.

I know my explanation of the reflection channel was a tad oversimplified, but I think a lot of us could do with things being explained in a simple and straightforward way sometimes.

Anyway, that's it for today. I hope you learned something while being here and as a treat for getting to the end of the post click the link below to download the scene file and see if what I said makes any sense.
The download contains the scene file in an R19 .c4d file format. plus .fbx and .obj files too. All the textures I made are also included and because I can't give you the HDRI I used (It's not mine to give away), I'm throwing in one of my own HDR images for you to use! More of which can be found here.

Anyway, thanks for stopping by and getting to the end of this post. See you next time.

PBR_Scene_file.