Erosion and water
Simulations turn clean procedural shapes into believable, weathered land. They are the heaviest nodes, so experiment at a low preview resolution. Because settings are in metres and years, the build matches.
Hydraulic erosion
Hydraulic Erosion simulates rivers carving branching valleys over geological time and dropping sediment where they slow down. Its settings include Duration, Rainfall, Rock softness, Sediment capacity, Deposition, Evaporation, Downcutting and Hillslope creep.
Besides the eroded Height, it outputs Flow, Wear, Deposition and Sediment masks, which are great for colouring river beds and sediment fans.
Two optional inputs shape where erosion acts:
- Strength: a mask limiting where it acts.
- Rock hardness: resists wear. Connect Rock Hardness for alternating soft and hard beds, which erode into stepped cliffs.
Thermal erosion
Thermal Erosion moves loose material down slopes steeper than the talus angle, building scree slopes. It outputs a Debris / Talus mask, which is ideal for the Debris / Rocks vegetation node.
A classic chain
Hydraulic Erosion → Thermal Erosion: water carves the valleys, then thermal erosion adds scree. The Scottish Highlands example uses 400,000 years of hydraulic erosion followed by thermal erosion.
Water
| Node | What it does |
|---|---|
| Rivers | Carves channels where drained area exceeds Source area, widening and deepening downstream, with optional meander. |
| Lakes | Fills hollows up to the level where each would overflow, with sediment-flattened beds. |
| Sea | Floods below Sea level from the world's edges and wears the coast into beaches. |
| Snow | Settles snow above the snow line, lower on shaded slopes, sliding off cliffs. |
Each water node outputs the modified Height, a Water surface heightfield and masks (for example River and Riverbank, or Sea, Shallows and Shoreline). Export the water surface separately to build water planes or meshes in your engine.
Hydrology masks
Flow and Wetness analyse where water would go without changing the terrain. Use them for vegetation and colour.