Water

Refraction off, then on: the posts shift at the surface and the floor darkens with depth.

• Refraction (rendering/pathtracing/refraction): water and glass blocks bend light by their IOR, with total internal reflection and depth tint; glTF KHR_materials_volume, KHR_materials_ior.
• Murky water (same setting): scattering media; IOR, ABSORPTION and SCATTERING in shaders; glTF KHR_materials_scatter draft.
• Caustics (rendering/pathtracing/caustics): sunlight lines under rippled water.
• Caustic cascades (rendering/pathtracing/caustics_cascades): sun caustics out to 256 m, near lines unchanged.
• Path-traced ocean (PhysXWaterSurface3D: pathtraced_absorption, pathtraced_scattering, pathtraced_roughness): waves refract, tint and scatter, with caustics on the seabed.
• Ocean swell (wave_cascades): up to four wave layers give long swell under the chop without visible tiling, whitecaps where they add up, on a shallow-water (TMA) spectrum; set depth to the real depth for open sea (the 3 m default damps long waves).
• Measured wave spreading (wave_spreading, swell): Donelan-Banner spreading as Horvath (2015) fits it, with swell; slopes at 14 m/s match Cox and Munk’s measurements.
• Raster reflections (raster_reflections on PhysXWaterSurface3D and PhysXRiver3D): raster sea and rivers reflect the sky and the sun’s glitter by the exact Fresnel term, matching the path tracer; raster waterfalls, white water, sea foam and wet sand take the scene’s shadows, sky light and cloud shadows.
• Lake ripples (automatic from fetch): on short fetches the wave grid gets finer, up to 256 points, so lakes keep their short wind ripples and sun glitter; open sea is unchanged.
• Whitecaps by wind speed (whitecap_auto, on; whitecap_cover_scale): whitecap cover follows the wind speed as measured at sea (Monahan 1980), whatever the wave settings.
• Finer water mesh up close (mesh_detail).
• Shore waves (shore_waves): swell turns with the seabed, grows in the shallows, breaks and runs up the sand (Stockdon run-up).
• Wave groups (shore_wave_groups): shore waves arrive in sets with their own Rayleigh heights, so each breaks at its own place.
• Plunging breakers (shore_wave_curl, shore_spray, shore_spray_amount): the crest throws a sheet of water that lands ahead and sinks into the bore, with spray where it is thin and where it lands.
• Currents (current, flow_period): flow round rocks and along shores carries waves, foam and floating objects.
• Faster flow bakes (physics/physx_3d/water/multigrid_flow): multigrid-preconditioned conjugate gradients bake the flow 7 to 10 times faster than SOR.
• Live flow (live_flow, wall_friction): near the player, rocks and banks shed wakes and eddies.
• Boat wakes (PhysXWaterWake3D.dispersive, breaking_slope): waves stepped with deep-water dispersion in Fourier space form the Kelvin pattern, a 19.5 degree wedge of transverse and diverging waves.
• White water (flow_foam): foam in fast water, trailing rocks and drifting downstream.
• Rivers (PhysXRiver3D: discharge, roughness, max_slope): drawn as a curve; finds its depth and never runs uphill.
  • Cascades into white water; carve emits channel brushes for a terrain deformer.
  • Rocks part the current and trail foam (obstacle_collision_mask); near the camera they shed eddies and a swinging wake (live_flow).
  • Joins lakes, the sea and other rivers (mouth_target), ponding to the water level; tributaries add their flow.
  • Waterfalls (fall_min_height): a falling sheet that thins, whitens and breaks up, with a boiling pool and spray.
  • Waterfall mist (fall_mist_amount, PhysXWaterMist3D): a simulated mist grid per fall, drawn as a raster FogVolume and path traced.
  • Living waterline (edge_lap_height, edge_relief, edge_foam): edges lap with the flow, look ragged and carry a thin foam band.
• Camera under water (path traced automatically; raster with underwater_enabled): fog, scattering, Snell’s window, image split at the water line.

Images#

Murky water: a green glow fills the deep end.

Caustics: bright lines on the pool floor.

Ocean: sand and caustic light through the water.

Ocean swell: one layer repeats the same foam patches; three layers add long swell.

Wave spreading: cos² gave long parallel crests; the measured spreading breaks them up, and swell adds long crests back.

Raster reflections: the flat dark sea now shows the sky and a band of sun glitter.

Whitecaps: with a fixed threshold the cover barely changes with the wind; now it grows from none at 6 m/s to many at 20 m/s.

Lake ripples: short wind waves and sun glitter on a lake, where the surface used to lie flat.

Shore waves: swell breaks into foam on the beach.

Run-up: the wash climbs the sand and drains back.

Plunging breakers: the sheet thrown off the crest, with spray along its thin edge.

Currents: the boxes drift past the rock.

Live flow: the streaks roll up into a wake behind the rock.

Boat wakes: before, a flat wedge; now transverse and diverging waves form the Kelvin pattern.

White water: foam peels off both sides of the rock.

Rivers: the cascade and the white water below it.

Rivers round rocks: foam trails behind the rock.

River live flow: the wake swings behind the rock.

River joins: two streams merge and spread into the lake.

Waterfall: the sheet breaks up into white water above the pool.

Waterfall mist: a haze now rises from the pool and drifts past the fall.

Waterfall lighting: the raster fall no longer glows white in the shade of the gorge.

Foam lighting: shore foam in shade is no longer bright white.

Under water: light scattering and the surface seen from below.