Original subtitles

To add that extra bit of life to our wall,

we'll spend the last few chapters incorporating moss into the shader.

Moss tends to grow in the cracks and crevices, so we can use a similar approach to what we did with

the mortar, with the idea of mixing shaders based on displacement depth. And in fact,

the texture that we made for the mortar works as a good starting point for the moss,

as moss also has this clumpy kind of texture.

So let's copy these few nodes, and remove them from the Frame.

Then, taking a look at the output of the Power node, we can adjust the texture parameters.

We can make the blobs a bit bigger in the Voronoi Texture,

and maybe also make the distortion texture bigger, and increase the intensity.

This is fine for now.

Now, to combine this with the wall, we can do the same thing we did with the mortar, but this

time even simpler. For the mortar, we had to combine it with the bricks before adding cracks,

and then use it to mask the cracks, so that they don't get filled with mortar.

But this time, we do want the moss to grow in the cracks as well,

so we can just plainly combine the moss after everything else, without any special handling.

So let's add a Math node onto the displacement map, set it to Maximum,

and plug in the moss texture.

Then, if we take a look at it,

we see that the low spots on the wall got filled with the moss texture.

We also want a mask of the moss, so just like with the mortar, let's duplicate this node,

and set it to Less Than. And this gives us a binary mask of where the moss is.

So far, we've been using a single Principled shader for everything, by just plugging

different textures into it's parameters. While we could do the same with the moss, its shader

is different enough that it's more practical to just use a new shader, and mix them together.

In a later chapter, we'll also be using some shading techniques which are not provided

by the Principled shader, so this setup will make that easier when the time comes.

So for now, let's just add a diffuse shader. Then let's make a bit of space here, and we'll also

need a Mix shader, not to be confused with the MixRGB node which we use for combining colors.

Then let's plug our shaders into the Mix shader, and plug the moss mask into the factor.

And let's take a look at the result. There's our moss,

though it's not exactly the right color, so let's tweak it to something more reasonable.

That's better.

One thing that sticks out is that all the rows that were offset deeper into the wall

are practically completely filled with moss, as the moss is totally flat, while the wall is not.

We do want the moss to grow in the low spots, but that should probably happen on a smaller scale,

while the moss should generally follow the larger depth variations in the wall.

Luckily, we already solved this same problem before, for the mortar.

So let's combine these two links with a Reroute. And then we can take the smooth variant of the

brick row offset, which we added onto the mortar, and add it onto the moss as well.

All we need is a Math node, and we can plug the offset in.

Now the moss follows the general shape of the wall,

and we can only see it in the smaller scale low spots.

Now looking at this displacement, perhaps the moss texture is a bit too intense, so let's duplicate

this Math node, and set it to multiply, so that we can control the texture intensity.

And now that we can see the moss on the wall,

we can do some final tweaking of the texture parameters, like making it a bit finer.

And maybe increasing the exponent, to make the clumps a bit chunkier.

That's looking good, so let's organize the node tree, and frame these nodes.

Let's not forget to give it a clear name, and we can also color code it, based on the moss color.

Then let's also frame these two nodes, like we did with the corresponding mortar nodes.

And copy over the node color.

Then we can snap everything into place, and our initial moss setup is done.