Terrain, real or imagined, built where the level lives.

Terrain is usually the first thing a level needs and the last thing to settle. A heightmap comes out of one program, the erosion out of another, the rivers get painted by hand, and every change upstream means doing all of it again. TerrainForge keeps the whole of it inside Unreal: a graph you edit in the editor, a preview that follows your edits, and a build that lands as a level.

The graph covers the full distance from an idea to a landscape. Place mountains, ranges, canyons, volcanoes, plateaus, islands and dunes where you want them; select by height, slope, facing or curvature; then let water, ice and gravity work on it. Rivers cut into rising rock until valleys branch, glaciers leave U-shaped troughs, cirques and moraines, cliffs shed scree, snow drifts into hollows and slides off steep faces. The simulation works in metres and years, so a setting means the same thing on a small map as on a large one.

Or begin with somewhere that exists. Search for a place, draw a square on the map, and TerrainForge brings in the best elevation published for it — lidar down to half a metre in France, Switzerland, the Netherlands, England, Norway, parts of Germany and the United States, and a worldwide model everywhere else — together with land cover and OpenStreetMap features as masks. Before you commit, it checks whether the place can become a playable level and says what it would have to fill in. Each source’s licence and the credit it asks for are recorded with the terrain, ready for your credits screen.

Every build is a take: the heightmap, paint weights, data maps, biome and PCG masks, and the lake and river geometry, kept side by side and never overwritten. Import the one you want as a new World Partition level — landscape, paint layers, lakes and rivers as engine water bodies, Nanite where it fits — and the large maps import from the command line, one region at a time, so they fit in a workstation’s memory.

The simulation that takes longest runs on your graphics card, several times faster, and every step that can use the card has a processor path too, so nothing depends on which one you have. And the graph, the builds, the real-world data, the import and the export are all open to an agent through the toolset, working on the same terrain as you and under the same rules.