Creating procedural textures is something that can be arduous process. When we planned Gaea’s feature set, color production was an integral part of it. With GeoGlyph 2, we introduced some of these ideas in rudimentary form. But with Gaea, we can fully express our new workflow and tools.
I set a test for myself to see how far I could take Gaea on a random terrain in 20 minutes. This was just to test our internal builds and see how the features held up in real scenarios.
What follows below is the breakdown of this terrain’s color production, and the reasoning behind each node. The latter is more important, in my opinion, because following a strict recipe will just give you the same results every time and eventually start making everything look homogeneous. But if you take the time to understand the individual concepts of the nodes, and how they are used, you can extrapolate the recipe into myriad new forms and create your own unique results.
The terrain itself is ridiculously simple. The idea is that you should be able to replace the terrain anytime and get comparable results for any other terrain by simply copying the color portion of the graph.
I started with a Dunes node, randomizing the Seed until a form with a central peak/ridge presented itself.
Next, the Dunes were eroded with high Rock Softness and Strength, as well as Base Level for Downcutting. As you can see, the duration was very, very low.
And the terrain was ready. The next step was to create a semi-arid texture for the entire terrain, including superficial vegetation.
Instead of trying to capture too much in one or two color nodes, I prefer creating several different textures and layering them on each other to create a more sophisticated, gritty result. Terrains should rarely be smooth.
For the base texture, I wanted two distinct textures: a light one for the higher and sharper areas like peaks, and a dark, dull texture for the lower areas. Mixing the two with the right mask will make it look like different materials (minerals and such) intermingling because of erosion. That is what we see in the real world that gives us such rich coloration in landscapes.
Note: Several nodes have been renamed. See the text descriptions to find out what each node is. This file will also be included in a near future build of Gaea so you can play with it yourself.
We begin with a Slope component. We capture the lower gradient, with a nice falloff. The falloff gives us subtle gradients over the steeper areas too.
The Slope is combined with the Wear output from the erosion node. A lot of the lower areas may look flat white, but combining the Wear has created almost imperceptible fluctuations in those areas that are too difficult to see in a black and white mask.
Finally, we apply a SatMap to the combined output. This gives us the nice, lighter toned peaks, and some darker patches at the base of some slopes, along with a wide, very light colored flow below them.
This is the distinct advantage of using and experimenting with SatMaps as opposed to creating your own gradient is that you will find lots of little unique things in different maps because they were created from actual satellite photos. It also helps achieve realistic coloration immediately.
Mud for low areas and flows
For the muddy, lower areas, we will use a Soil map. It creates a bit more broken shapes and flows compared to a Slope map. The flows are very important here because we want to show flowing minerals intermingling in the final map.
A dark SatMap is applied to the Soil Map. I used Jitter to make the source gradient a bit rougher. This gives the mud a nice gritty texture.
Finally, we blend the two using the Slope map from before as the mask. Notice how the light color flow blends into the darker flows, and some of the sharper (steeper) edges of the stream in the top half benefits from getting elements from both color maps.
To create the vegetation, we need to map out the areas where vegetation would grow in such an environment, and do it in a noisy way — as in, create a mask with lots of little pinpricks to create the kind of variations in the color map we would need for distant vegetation.
I used two source maps for vegetation — both of them Surfacers. The first one used Sprinkling to get a wide spread.
The second Surfacer uses Peaks to get the sharper areas and small creases within fluvial grooves.
The two sources are then combined with equal blending.
The source map is then passed to another SatMap. This time I used a full green map with several fluctuations, but nothing too chaotic. This seems very lush and green, but when combined with the mud and stones, it will look dark and somewhat arid.
To pull that off, we create another Slope map, targeting just the 64º gradient, but using the falloff to capture 13% of the adjoining slope range. This range was chosen by experimenting to find the low gradient right where the large slopes end, but before the mud flows start. In real life, vegetation would indeed grow in such an area.
The vegetation and our base texture are combined using that slope mask. This gives us this nice, crinkly vegetation shapes across the map, but does not overpower. Since we target the lower slopes, it looks even less populated when you see it in 3D because of the perception created by a slope.
Finally, the color map is Autolevelled using ColorFx to bring out the differences between the darker and lighter tones and add some general grittiness.
Wear and Tear
There is always some sort of wear and tear on any terrain. Instead of using Erosion data, I prefer calculating it separately. There is no fixed way of doing this — you can use Curvature, for example. In this case, I used the Wind Streaks mode in Surfacer.
A medium setting in Surfacer using the Wind Streaks mode gives you these beautiful streaks that can be used in so many ways. Note that the darker areas may look dark, but they’re full of subtle streaks that will come out with the right color map.
By applying this highly varied SatMap to the streaks, we get these great colors. I tried to kept the tonality light, so it wouldn’t affect the main texture too much. This pass is meant to be very superficial.
I used the Min mode to combine the streaks. This largely ignores the light tones and only integrates the darker ones, which further adds to the grittiness of the texture. Because the wind streaks are so different from the usual flowing shapes in all the other components we used (Soil, Slope, etc.), the disturbances it adds are very different and break up the slight monotony of the finer details in the texture map.
And the color map is completed!
The entire process took me roughly 20 minutes, including trial and error. Now this recipe is in my personal library (and soon will be in yours too as it will be included in Gaea’s quickstarts collection). If I need a different terrain with the same general coloration, I can just replace the Dunes and Erosion node with anything else and it will produce a full color map in moments.
Future Color Production Tooling
The current color production tools in Gaea 1.0 represent just a small margin of all the tools we have in production (not to mention those in R&D).
These tools, including a whole new mode for Color Production, will be slowly released between Gaea 1.2 and 1.5 over the next several months. We will cover those in separate tutorials in the future.
Extra Icelandic Scene
Later, I turned the terrain into a quick and simple scene.
I won’t go into specific details of creating the scene as it is beyond the scope of this article, but here is the general rundown:
First, a plane was displaced with the heightmap (4096 x 4096) from the terrain, and the color map was applied on it.
The terrain was duplicated a couple of times and increased in scale, and placed in the distance to create further mountain slopes.
The color map from Gaea was desaturated further to make it fit the Icelandic hotsprings-like tone I wanted for this specific scene. (The terrain was originally meant to be similar to an arid, rocky, desert environment.)
A combined Veg Mask and grayscale version of the color map was used for the bump channel in the material. This helped bring out the crinkly shadows to go along with the crinkly color spots.
I placed a few Iceland rock scans courtesy of Megascans in the immediate foreground, along scattering a few hundred stone models.
There was very little postwork except color correction, adding a few lens effects, and painting a bit of mist. The lighting was fully procedural using a single light source (Corona Sun) and Corona Sky for the ambient light.
For a higher quality version, and additional shots, see the post on Artstation.