#3 - First Terrain Materials + Grass Improvement

Terrain Materials

This week I started work on some simple, painterly terrain materials in Substance Designer. This took a few iterations to get right, but I'm quite happy with how they've turned out.

The setup for grass in Designer looks like this:

A lot of this graph is redundant however, most of the stuff in the top right, specifically. I originally wanted to add patches of clovers and flowers, but this detail was far too obvious when tiled. In addition, it interfered with the Runtime Virtual Texture (RVT) setup I'm using for my grass mesh. So the final version is just plain, fuzzy grass.

The Dirt and Path materials share very similar graphs, the only difference being a few tweaks to colours and a different random seed.

The bulk of both graphs is the use of the "Slope Blur" node, which (with the right inputs) produces some interesting brushstroke effects. I generated a couple of variations of these brush patterns, then scattered them about using the Tile Sampler node. These got fed into a Gradient Map node to assign colours to the greyscale image.

A detailed normal map wasn't very important for this sort of style, but I generated a subtle one by lightly blurring the brush pattern. I also used this blurred version to create some subtle ambient occlusion to add a bit of shading.

To avoid using an extra texture sample for Ambient Occlusion in UE5, I simply mixed the Base Colour with the AO, which I think works for this particular style.

These materials aren't particularly exciting. For the Dirt/Path especially I could probably push them further, with some smaller details layered on top, like small stones and such, but they work fine for now.

Grass Improvements

As well as terrain materials, I also spent time troubleshooting my grass shader, which just wasn't shading quite right:

Each blade of grass was very obvious, highlighting how low-poly the blades were, as well as introducing a lot of visual noise. In addition (and not pictured above) the grass was way too shiny, particularly on slopes.

After the fix, the grass looked like this:

Much fluffier, much softer, and now each blade blends together into clumps, which more closely mirrors the look of my painted references.

The solution was related to the grass normals, as well as my decision to use the "two-sided foliage" shading model.

By default, each blade of grass had it's own normals, pointing off in all directions. As I posted about in production post #1, I thought I'd correctly adjusted the normals to point upwards, turns out I'd gone about it using the wrong method in Blender. 

A video by Prismatica Dev here showed me the error of my ways, and demonstrated a trick to cheaply fix the normals using the TransformVector node. Now the normals of each grass blade point outward, effectively copying the normals of the landscape. 

The result being, the grass now shades almost exactly the same as the underlying landscape.

To take it a step further, I implemented a shimmering wind effect, which I've seen done by a number of artists, such as Christian Sparks, and Victoria Zavhorodnia.

This effect pans a noise mask in world space, across the grass. This mask is used to lerp between the regular grass colour and a "highlight" colour parameter.

The mask, made in photoshop looks like this:

And panned across the landscape it looks like this:

Not sure how well it works, but I also added an effect that stretches and squashes the grass blades up and down, based on the colour of the mask. This gives the grass as a whole a subtle "wave" as the highlights pass over.

Going forwards, I need to pick up the pace a bit and get going with the building.

Right now I have a Grass, Dirt, and Path material set up (which, from the current angle you see the scene from, you can't even really see), but I really need to get on and get cliff and snow materials made, and then get going with sculpting stuff for the building, otherwise I'm going to run out of time.

I'm having doubts about the landscape itself now as well. It seemed promising at first, but I'm now starting to wonder if it's just too expansive for two reasons: 

• The number of rocks, trees, bushes, and other foliage I'll need to fill it all out might be too much work with the time I have.
• Right now, there's vast expanses of nothing. The mountains on either side take up so much of the frame, but lack any real visual interest.
• On the other hand, there's a bridge, a house, a mountain, and (3!?) windmills, all vying for attention. Is that too much?

Might it be more practical (and also a better composition) to slim it right down, focus on a smaller space, and in that space, focus on one really solid focal-point? Probably.