Canyon material using advanced procedurals and Vertex Colours

Bump maps continued

Now that the mud is finished, lets tackle the canyon wall bump. A couple of words of advice before I start. I started out with big bump maps, then proceeded to layer progressively smaller bump maps to get fine detail, and to make sure the there wouldn't be any areas that were flat (sort of how painters block out the shapes first and then proceed to add finer and finer detail). Since I use the High/Low settings extensively, I run the risk of having completely flat areas in my bump maps, and the easiest way to solve that is to throw yet another map in the colour slot or put the map in a mix map. This will enable you to get nice detail pretty quick, but you also get a fairly deep material tree. That's why the canyon wall bump map might seem a little chaotic at first, but there really is some thought behind it all. Honest. See for yourselves!

Hop on back to the first mix map we put there which I named "canyon wall and mud bump". In the first slot we now have the mud bump, and in the second slot we put a mix map (surprise!). Name this one "canyon wall bump". In the first slot, we will put yet another mix map named "sediment and wall bump" where we will mix that lovely Gradient Ramp from the Diffuse map and the rest of the bump maps.
In slot two, put a copy of the Gradient Ramp map, the one from the diffuse map, named "sediment lines".

Here's another little gotcha. You can just instance it, and it would work fine, but if you want to give have some extra lines in the bump map, you will get extra lines in the diffuse map which might or might not be needed. What I did was just copy the sediment line map, then convert it to greyscale by hand. It's pretty tedious, but it gives you a fair representation of how it will look, and you can always add more lines without worrying about the diffuse map. It's up to you how you want to do it. Here's a side by side (or rather, above/below?) comparison of the two different gradient ramps.

As you can tell, the lower one will give a more detailed bumpmap, with a little more contrast. Now, if you had instanced the diffuse map, the would probably have some bright lines that would stand out. In order to fix that, you'd have to play with an Output map, or maybe the RGB Multiply map. I've set up a separate page where you can see the difference in the scene. Please take a moment to check that one out.

Back to the bump map creating. Now that you've finished fiddling with the Gradient Ramp, it's time to get started with the rocky bump itself.

Go back up to "sediment and wall bump mix" and slap a Mix map in slot 1 called "wall bump". Put an Output map in the first slot, name it "small bump strength control". This is to control the effect it will have on the end result. Sticking in an output map here and there lets you fine tune the bump map features, which is good. Control is always good.
Once again, put a Mix map in the Output map and name it "large and small mix" Slot one will use an Electric Map called "smaller rocky bump".
Put a Noise map named "flat area fix" in the black colour slot of the Electric map. This will ensure that no black areas will be perfectly flat.

Since I have tweaked the High/Low settings on "smaller rocky bump", I have rather large completely black areas. The "flat area fix" will deal with those, and together with ther other layered bump maps, create a nice and rich surface.

Go back up a few levels to the "large and small mix" Mix map and put an Electric map in slot two. Name it larger rocky bump".
To finish of this Mix map, put a Noise map in the mix amount slot, name it "general noise".
There's only two Noise maps left to apply. Go back up to the "wall bump" Mix map, where you have the "small bump strength control" in slot one. In slot two, put a Noise map, named "subtle detail".
Now for the last Noise map. Go up to "canyon wall bump" and put a Noise map in slot two. Name it "minimal noise". This one will add a fine bump on top of everything. With the mix amount spinner you can control how much it will show, and I recommend a low value (less than 20) since it's supposed to be a subtle effect.