Rain first wets the soil, then collects in low ground. Lakes rise until they find a spillway, while concentrated flow can cut a channel. Try Lake basin & spillway with Wet & dry cycles. Use Evaporation to control how long ponds and lakes persist.
Drag to pan the map; scroll or pinch to zoom. The optional 3D view supports orbiting and right-drag panning. Select Raise, Carve, or Rain and paint directly on the terrain. Space pauses; R restores the original terrain.
Switch to Geology to inspect warped soft and resistant rock layers. They affect incision and soil permeability. Import a grayscale heightmap to use real elevation data: black is low, white is high; geology remains procedural.
This MVP uses solid voxel columns: it models the exposed surface, without caves or overhangs. Geological years are illustrative. At large sizes, the view samples a coarser surface while the solver retains the full resolution. GPU timing appears when the browser supports timer queries.