¶ Overview
The auctoria Terrain is a fast and intuitive AI-powered system that lets you generate complex terrains with just a few clicks.
¶ Introduction to the Terrain Building Module with a Simple Example
The terrain building module allows you to build a static terrain mesh covering 2.25 [km²] (a square measuring 1,500 meters or 0.932 miles on each side).
¶ Segment Map
Terrain Segment Map is a 2048×2048 pixel image that represents a simplified version of a three-dimensional terrain generated by AI. Each segment is distinguished by a unique 2D shape and color. The number of segments and their colors depend on the selected AI model.
In the example below, the Earth_1 model is used, which defines the following segments:
- Ocean – generates flat and smooth terrain, corresponding to the ocean floor.
- Desert – a relatively flat and low-lying area, which may feature sand dunes.
- Meadow – a lowland, flat area with gentle terrain.
- Tundra – flat or slightly undulating terrain.
- Mountains – depending on neighboring segments, may form hills, uplands, or mountains.
- High Mountains (Peaks) – sharp, pointed mountain peaks.
You don't need to create a highly detailed Segment Map, but keep in mind that it has a 2K resolution and covers a large area. Therefore, it's worth – and recommended – to include more information by adding a variety of segments with different shapes. It's also important how you blend your segments – for example, mountain peaks typically don't rise directly from the ocean. The example in this tutorial uses a map, as shown in the image below.
¶ Generator
Once you have painted the Segment Map, you can preview what your 3D terrain will look like by clicking the REGENERATE button in the preview window at the bottom.
Another way to preview the terrain, this time directly in Unreal Engine, is by adding a Canvas object to the scene. To do this, click the CANVAS button. The in-engine preview is less accurate, but it's necessary for determining the direction of the light — which has a significant impact on the final result, as will be discussed later.
To generate the terrain, simply click the BUILD TERRAIN button. After a few minutes, you should see a result similar to the one below.
The tutorial above includes the minimum steps required to generate terrain.
¶ Bioms and Filters
A Biome is a large geographical area characterized by a specific climate, soil type, vegetation, and wildlife. In the auctoria system, the choice of biome affects the default values of filters, textures and material layer constructs (shaders).
All Filters, except for the height of the terrain (HEIGHT), need to be re-generated (REGENERATE button) if you want to make changes. The filters include: erosion, dilatation, aggregation, groove, water level, vignette, border and height.
¶ Erosion
Erosion is like a delicate smoothing of the terrain, which removes small irregularities and makes the whole look more natural. However, remember that it is a filter and not a complex simulation, so too high a value of this filter can lead to undesirable results.
¶ Dilatation
Dilation is like a gentle expansion of elements on your map. It makes objects slightly larger and more distinct, as if they have spread outwards. However, remember that it is just a filter, not a complex simulation, so too high a value of dilation can cause details to merge and the map to lose precision.
¶ Aggregation
Aggregation is like merging or combining elements on your map. Imagine you have small, scattered points on the map. Aggregation causes these points to stick together, creating larger, more compact areas. It's a bit like collecting small pebbles and forming larger boulders from them.
¶ Groove
Groove is like excavating grooves and depressions on your map. Imagine you have delicate furrows and indentations on the map. The Groove filter makes these furrows deeper and more pronounced, as if someone has sculpted them intentionally. It's a bit like deepening rivers and valleys to make them more visible and distinct.
The effect may not be very noticeable in the preview window, but the final look is as below (rock samples).
¶ Water Level
The Water Level filter affects the level of the coastline (e.g. in an island biome, the higher the water level value, the higher the beach will be). The Water Level filter makes everything below the set water level flatter and smoother, as if water filled all the unevenness.
Of course, at this scale, as with the Groove filter, the effect may not be very noticeable in the preview window.
¶ Vignette
Vignette is a filter that gently lowers the terrain height at the edges of the map, allowing the area to gradually slope down toward the borders instead of ending abruptly. This makes the terrain look more natural and blend smoothly into the surroundings — without appearing 'cut off' or artificial.
¶ Border
Border is a filter that lowers the terrain at the edges of the map to prevent odd gaps visible from the side.
¶ Height
The mesh height of the terrain affects the overall height of the map, but the optimal value is between 10 and 30.
¶ Simulations
Simulations are algorithms that, due to requiring more calculations, run a bit slower than filters and can be executed after the terrain has been generated (using the REGENERATE button). The current version of auctoria includes three optional terrain simulations (tectonic plate, player route, cone trimming) and one required simulation — daily sunlight insolation — which does not have a separate button (it runs automatically when BUILD TERRAIN is clicked).
¶ Tectonic Plate
Mountain formation can be caused by the collision of tectonic plates (convergence), which leads to one plate being subducted beneath another (subduction). The tectonic plate simulation analyzes the generated terrain for the potential formation of mountains due to subduction and enhances this effect.
The part of the terrain identified as the overriding plate is further pulled upward, as shown in the image below.
Elevating parts of the terrain results in the formation of cliffs, enhancing the visual appeal of your landscape.
¶ Route Simulation
Route Simulation is an algorithm that generates a hypothetical player route — it does not create a navigational path (such as the Navigation Path in Unreal Engine), but rather a visually defined route shaped directly into the terrain. The path runs through scenic viewpoints that could have formed naturally, just like in real landscapes. The algorithm includes multiple mechanisms for route generation and a very fast method for estimating the terrain's visual sensitivity map, which serves as the foundation of the algorithm.
Each simulation has its own preview window, allowing you to accept the result or run it again. Currently, in the case of the route simulation, it is a deterministic process — without added noise — so repeating it produces the same result every time (in the current version of the system).
The generated path is created in such a way that it blends smoothly into the terrain and remains as unobtrusive as possible. However, its main purpose is to ensure smooth movement for the player, so when necessary, it can cut through mountains, forming ravines or natural bridges to soften overly steep slopes.
¶ Cone Trimming
The current version of the system generates terrain using around 0.5 million triangles, which can result in sharp mountain peaks. Cone trimming is an algorithm that analyzes the terrain and removes unnaturally pointed shapes. You can run this algorithm as many times as you like (it is recommended to use it at least once; running it more than four times may have no additional effect).
¶ Daytime Insolation
Daytime insolation simulation requires setting the angle of sunlight (Directional Light in Unreal Engine). If no light source has been added to the scene, default values for the sun’s azimuth and elevation are used.
You can adjust the light angle in Unreal Engine using the Ctrl+Alt+L shortcut — holding this combination allows you to change the light angle using mouse movement. The insolation simulation is mandatory, so it doesn’t have a separate button — it starts automatically after clicking the BUILD TERRAIN button.
The sun position set by the user represents its highest point in the sky during the day (solar noon). The simulation assumes that solar angles before and after this point (sunrise and sunset) are correspondingly lower. The maximum solar elevation depends on the geographic latitude — the closer to the equator, the higher the sun's position at noon (up to zenith). This peak solar position serves as the basis for calculating sunlight exposure across different terrain areas. Based on this, the system determines the distribution of light and shadow, which affects predictions of microclimatic conditions such as potential locations for the growth of mosses, lichens, and other.
¶ Final Settings
The current version of Unreal Engine (5.5) does not allow for efficient use of Nanite tessellation and RVT blending at the same time, so you’ll need to choose which effect you want to use in your scene. Tessellation allows for a high level of detail, while RVT blending provides smooth transitions between the terrain and the rock formations you’ll add in the next stages of scene preparation.
¶ Nanite Displacement Tessellation
Nanite Displacement Tessellation is a technique in Unreal Engine that combines Nanite technology with displacement, allowing for dynamic modification of 3D mesh geometry in real time based on displacement maps. This enables highly detailed surfaces without the need to manually increase the polygon count of the base model.
The materials generated after building the terrain (BUILD TERRAIN) already include displacement maps, so all you need to do is configure and enable Nanite. To do this, select your object and, after opening the context menu (right-click), choose Enable Nanite.
Now enable tessellation in the terrain material, as shown in the image below.
When the pin named Displacement becomes active in the material, as shown in the image below, connect it to the Displacement output from the Attributes node.
You can adjust the displacement height using the parameters shown in the image below (Magnitude and Center).
¶ RVT Blending
RVT settings do not affect the appearance of the terrain, but in order for your rock formations to blend smoothly with the terrain, it is necessary to perform a few operations. First, locate the two RuntimeVirtualTextureVolume objects that were created after building the terrain (they should be named XXX_Volume_ML_Color and XXX_Volume_ML_Height, where XXX is the name of your project). In the next step, you’ll adjust their volume bounds.
Click the eyedropper tool (pipette) as shown above, then click on the terrain, and finally press the Set Bounds button as shown in the image below — you should see the Transform values update automatically.
Now set the virtual textures for the terrain. To do this, click twice on the plus icon (shown in the image below) and select two RVT textures, which should be named RVT_ML_Color and RVT_ML_Height — the order doesn’t matter.
These are all the necessary settings, but if you want to change the blending quality, you can do so by using the option shown in the image below (double-click on the RVT texture).
This tutorial is focused on terrain, not rocks, so it does not describe the settings related to rock formations. However, you can see the result of the blending on rock formations in the image below.
(tip: for a perfect result, move the terrain to the location: 0,0,0)