Erosion & Drainage
Nature's sculpting tool. Water finds the path of least resistance and leaves its mark.
Hydraulic Erosion
The hydraulic erosion simulator drops thousands of virtual water droplets onto the terrain. Each droplet follows gravity downhill, picking up sediment where flow is fast and depositing it where flow slows down. Over thousands of iterations, this carves realistic channels, gullies, and alluvial fans into the surface.
The result: terrain that looks like it was shaped by actual rainfall over geological time. Ridges develop natural drainage patterns. Valleys collect sediment. Peaks erode into rounded forms.
Fractal Drainage
On top of hydraulic erosion, Terraformer overlays a fractal drainage network — the kind of branching river patterns you see from a satellite. These channels are algorithmically generated to follow the terrain's gradient field, producing coherent watershed boundaries and tributary systems.
Fractal drainage integrates with the erosion results. Where erosion has already carved a channel, the drainage network follows. Where the terrain is flat, drainage creates new branching patterns.
Erosion Parameters
| Parameter | What It Controls |
|---|---|
| Iterations | Number of water droplets simulated. More = deeper, more detailed channels |
| Erosion Rate | How aggressively water removes sediment. Higher = deeper cuts |
| Deposition Rate | How quickly sediment settles in slow-flow areas |
| Evaporation | How quickly droplets lose water. Higher = shorter channels |
| Channel Depth | Depth multiplier for fractal drainage channels |
Hydraulic erosion runs first, carving the initial channels. Fractal drainage runs second, overlaying coherent river networks that respect the erosion results. The combination produces terrains with both the fine-grained detail of particle erosion and the large-scale coherence of watershed hydrology.