Plate-Local River Generation: Deterministic, Terrain-Aware, Downhill-Flowing Rivers for Infinite Procedural Worlds

arXiv cs.GR details a deterministic, terrain-aware river generation method aimed at infinite procedural worlds. The core idea is to make rivers practical for worlds that stream forever without breaking the downhill-flow guarantees that terrain teams usually want.

The system uses tectonic plate seeds to define both the terrain field and bounded plate domains, so river preprocessing can happen locally on each plate. Within a plate, the terrain is sampled on a low-resolution grid, rivers are traced from highlands to coastlines, minima, or confluences, and each segment is adjusted so stored river heights always descend.

Because the river network is generated and cached lazily per plate, each region can be processed independently of its neighbors. At full resolution, the engine computes distance to the cached river network exactly, then interpolates river height and blends it with the local terrain on demand instead of caching the blended result.

For developers building large procedural worlds, the practical win is coherence without global preprocessing. The paper argues that bounded plate-border warp and a river border margin are enough to guarantee downhill flow in the final terrain, making terrain-aware rivers more viable for interactive streaming worlds.