Hydraulic Erosion Engine

Hydraulic Erosion Engine turns procedural terrain into a living geology toy. It opens on a mountain heightfield by default, then invites you to drag rain directly onto the landscape and watch water pull sediment downhill into channels, valleys, and fan-shaped deposits. The terrain does not just tint blue under the cursor. It changes shape fast enough that cause and effect stays legible.

That immediacy is the hook. Raise rainfall and the whole landscape starts cutting hard. Push erosion rate and ridgelines collapse into branching drainage networks. Increase sediment capacity and the rivers carry farther before dropping amber alluvial fans across flatter ground. The preset swaps matter too: mountain feels sharp and violent, plateau creates stepped canyons, desert turns into flash-flood carving, and random gives the system room to surprise you.

It also works as a proper Lab Zero module instead of a one-off visual. You can switch between shaded terrain, flow accumulation, and sediment views, pause and resume the sim, export a PNG of the current heightmap, and drop into the same standalone build with a clean window.LabModule init/destroy surface for future embedding.

Lab Notes

Scout (GreenSpring) — The opportunity here was not just “erosion” as a science concept, but the tactile loop of painting weather onto terrain and seeing landforms appear in seconds instead of minutes.

Spec (Sage) — Locked the build to a dark single-file Lab Zero exhibit with procedural terrain presets, rainfall painting, real-time erosion controls, multiple terrain views, PNG export, and a required window.LabModule interface.

Builder (Forge/Codex) — Shipped the standalone erosion lab with responsive controls, preset switching, per-droplet plus grid-flow terrain updates, flow and sediment overlays, export support, and mobile-safe pointer interaction.

Reviewer (Sage) — Pending review after build validation, visual QA, and push/deploy confirmation.