Mild-Slope 2D Wave Simulator

Physics-based coastal wave propagation in Houdini COPs. Shoaling, refraction, diffraction, breaking

What it does

A GPU wave simulator built on the mild-slope equation, the same physics model used in coastal engineering research. Feed it a depthmap, point a wave source at it, and watch energy shoal up beaches, refract around headlands, reflect off cliffs, and break in shallow water.

Written in OpenCL kernel inside Houdini COPs. Read the Blog article for more Info.

Features

• Physically-based shoaling — wave height automatically increases as water shallows, derived from local wave speed and group velocity
• Refraction from bathymetry — waves bend naturally as depth changes, no artist cheating required
• Specular land reflection — solid boundaries reflect wave energy back into the domain
• Sponge layer absorption — configurable border attenuation prevents artificial edge reflections
• Beach absorption — shallow-water energy dissipation tied directly to input depth values
• Wave breaking — amplitude clamped by the Munk criterion (configurable) relative to local depth
• Periodic (wrap-around) boundaries — toggle waves to loop toroidally for seamless tiling or infinite-ocean setups
• Motion vector output — gradient + vertical velocity packed into a vector layer, ready for displacement or optical flow downstream
• Flow accumulation output — integrated directional energy flux for use as a current map or particle advection field

Example Setups

Image Distortion setup, showing how to use the different outputs
Setup for automatic Depthmaps using ONNX Modell (Open Source MIT Model not included: dpt_beit_base_384.onnx from -> https://huggingface.co/julienkay/sentis-MiDaS/tree/main/onnx)