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With the Color channel complete we can move onto the Diffusion channel. The Diffusion channel is often called the dirt channel in a lot of 3D circles and the reason for that is it's the place where you give your objects character and add dirt to your materials. Now for our shark, we are going to be adding things that basically just look like modeling on the surface of the shark and scratches and just general texture that sort of breaks up the flatness of the gray on the shark, so that it's not just a perfect flat color all the way around. So we are using the Diffusion channel for that.
So here in my layout, I'm going to select a brush and I am going to be working in Projection Painting just like I was before, but I want to be careful about which channel I am painting in. So let's start off by selecting the right brush. I will go to the Brush tab and scrub down. I will close up Long Weekend and scrub all the way down to the BodyPaint 3-D Artist Brushes, and these are some excellent presets that are included with CINEMA 4D. We are going to go to the Dubtastic collection. For the Diffusion channel we are going to use Dumpster 05 and the Dumpster 05 is really just a grunge pattern and that's going to be perfect for just adding a sort of mottling to the surface of our shark.
Before we switch to Projection Painting mode, we have to double check our layers and go to the Colors option, and then remember the Colors is where you determine what channel you are painting in. So I am going to turn off Color by clicking on the pencil there and then click on the Diffusion channel and make sure that its pencil is active. So now the D stands for Diffusion, so I am painting in the Diffusion channel and I am going to be painting a color. Now I can go to the Layers palette and let's add a new layer to our diffusion. So I will go to the Function menu > New Layer, and I don't need to name this layer because it's really going to be the only layer that we have in the Diffusion channel.
So now, I can go back to Colors and check what color I am painting and let's paint a fairly dark gray pattern. Now when you move your brush over the surface of your object when you're not in Projection Painting, you really get to see that breakup of the UVs and so Projection Painting fixes all that, so it's always a good idea to paint in Projection Painting. So I am going to switch to Projection Painting and now when I paint across the surface of my shark, it's going to paint a single pattern. So let's switch to a more side-on view and then just click one time with the brush, boom! Now, our shark looks like it is a crack sidewalk now, but that's okay because we are going to be cleaning up this material a little bit and really just adjusting the Opacity on everything so that it blends a little bit better with our other channels.
So let's orbit around to the other side and do the same thing. I orbit to another kind of side-on view, and then just click one time, boom! And then just check the top. You can see that there's a little bit of a seam there on the top and this time I'll need to add a new layer. So I am going to disable Projection Painting, go to my Layers palette, and then let's add a new layer. This one we are going to call Top. Then we'll switchback to Projection Painting mode and we are going to just click one time.
I don't want to paint in here on the tail. I am just going to click right in this area, so you can see my brush is not overlapping the tail area at all. So I will click one time right on that, and then we can do the same thing for the underside. So let's disable Projection Painting and then go to the Layers and let's go Function > New Layer and let's call this one Bottom. Then go back to Projection Painting. We will orbit around all the way to the underside of our shark and then with Projection Painting active, I am going to click one time, bam! Now I have got this sort of mottled pattern all over the surface of my shark, but it's overwhelming everything.
So I just need to adjust the opacities of these layers now. So let's get out of Projection Painting mode so that we can see our layers. Now we can adjust the opacities on them. So on the bottom layer, by moving the slider to the left, I can adjust that. So let's switch around in orbit, so we can see the underside of our shark. And I'll just drag that down to about I don't know. Let's call it to about 17% or so. Let's do that for the top and the sides as well. So I will click on the top, let's orbit around so we can see the top, and bring that down a little bit as well. There we go.
It's always a good idea-- You should never really trust what's happening-in in the Editor view. I always like to do a Command+ R, so I can see my material. Now, we still haven't done the sides yet, so let's go to the sides which are in this layer here, and let's rename this layer so we know what we are looking at, and then call this Sides. In the Sides layer, let's drag this down to about 17% or so. There we go, and actually a little bit less. That's quite a bit of mottling on our shark. So now when we orbit around, we can see that these layers blend together quite a bit better.
Now, you know 17% when I render is still a little bit heavy I think, but it's not too bad. I am just going to dial them down just a little bit more. I am going to take them all to 10%. So the Sides is already at 10, and let's bring this down to 10, and this one down to 10 as well. Then just do another render in Command+ R. You can see that just smooth things out a little bit better. So the great thing about working in the Diffusion channel is that it allows you to keep these scratch marks and dirty sort of modeling on the surface of your shark separate from the Color channel, and it really allows you to subdivide the texturing process in some manageable chunks.
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