Capabilities of the Water System

The Water System simulates the behavior of water surfaces. It is adjustable and customizable. A scene can support multiple water surfaces simultaneously.

Water body types

HDRP provides for three water surface types: Pool, River, and Ocean, Sea, or Lake. The last two of these include multi-band simulation properties to provide larger and more complex wave patterns.

Underwater rendering

It is possible to view water surfaces from below if you enable the Underwater option.

Wind and current

Wind and swell or ripple properties combine with Current values to determine the motion of the water simulation.

Surface foam

River and Ocean, Sea, or Lake surfaces support surface foam. You can adjust the amount of foam, its smoothness and texture, mask it, and adjust it based on the Distant Wind Speed.

Caustics

You can adjust caustic resolution for all surface types, and specify which Simulation Band Unity should use to generate the caustic texture for River and Ocean, Sea, or Lake surface types.

Material properties

It is possible to adjust the Smoothness, Refraction, and light Scattering qualities of a water surface.

ShaderGraph

For more in-depth water Material customizations, you can use the water ShaderGraph.

Masking

You can assign custom masks to attenuate or supress ripples, swells, and foam on specific portions of a water surface. You can also use them to adjust decal and light layers.

Scripting

It is possible to create scripts that interact with the Water System, to imitate buoyancy, for example.

Limitations and caveats

The Water System does not currently support:

  • Breaking waves on shorelines
  • Holes
  • Views from the side (as in an aquarium)
  • Rejection (to keep the water surface out of hollow objects, such as boats)

Foam and caustics are monochrome.

Feature compatibility

The Water System is compatible with most HDRP and Unity features, with some specific exceptions.

Lighting

You cannot bake lighting for a water surface.

Volumetric Clouds

Water renders in front of Volumetric Clouds if you view it from above.

Lens Flare

Water surfaces do not occlude Lens Flares. This produces an unnatural effect when you look upward at a Lens Flare from underwater.

Dynamic resolution and antialiasing

HDRP's water implementation does not use motion vectors. This means that techniques like Deep learning super sampling, and temporal antialiasing produce blurry results with a lot of ghosting if you use them with water. Multisample anti-aliasing is entirely incompatible with water, however.

Raytracing caveats

Although water surfaces can receive Ray-Traced Reflections, they cannot contribute to them. This means if you hold up a mirror to a water surface, the water does not reflect in the mirror, for example.

Reflection and refraction

Water surfaces do not affect transparent refractive objects. Also, although Screen Space Reflection is compatible with water surfaces, it does not fall back to Reflection Probes underwater.

Decals

HDRP provides limited decal support for water surfaces. Global opacity controls the strength of the decal influence. Also, certain Decal Shader Surface Options do not work with water surfaces:

  • Affect Metal
  • Affect Ambient Occlusion
  • Affect Emission

Also, Affect Base Color only produces monochromatic output.

Additional resources