Fluid Rendering Components

Fluid Renderer

The Fluid Renderer component is responsible for rendering the Fluid Simulation. This component is in charge of creating and rendering the necessary meshes and materials needed for displaying the assigned Fluid Simulation. Users can customize the Fluid Renderer component to create their own rendering effects, similar to Water Surface and Lava Surface renderers.

Property	Description
Debug Mode	Different fluid debugging modes that can be used in the editor.
Surface Properties	Properties that determine the mesh quality and the specific drawing mode of the fluid surface. This structure holds settings that control the visual fidelity and performance of the fluid surface mesh. This includes the specific method used to render the mesh, such as standard MeshRenderer, procedural drawing, GPULOD, or a specialized HDRP mode.
Fluid Material	The material to be used to render the fluid surface. This material is internally instantiated at runtime. The component copies the properties from the original material to the new instance, and then overrides or injects any necessary rendering requirements (e.g., shader keywords or properties) for the fluid simulation effects to function correctly.
Simulation	The Fluid Simulation component that this renderer will draw. This is a mandatory dependency. The FluidRenderer will automatically adopt the world-space dimensions and position of the assigned Fluid Simulation, ensuring the rendered fluid surface matches the simulated area exactly.
Flow Mapping	The Fluid Flow Mapping component that this Fluid Renderer uses to visualize fluid currents and wakes. This component provides the necessary data to the fluid shader, which can be either a dedicated flow map texture (for dynamic UV-offsetting) or material parameters derived directly from the simulation’s velocity texture. This allows the fluid surface to depict accurate movement and flow.
Render Skirts	Renders downward skirts at the edges of the fluid surface.

Fluid World Renderer

Fluid World Renderer draws multiple Fluid Simulation tiles as one continuous surface. Use it for open oceans, large lakes, and any scene where simulation is split across several domains but should look and behave like a single body of water (or other fluid type).

The component always renders with GPULOD. Each frame it gathers matching simulation tiles in the scene, composites their height, normal, terrain, foam, and flow data, and draws one world-scale surface from that combined result. You configure the footprint, material, channels, and optional ocean/detail-wave layers in the Inspector on this one object.

For water-specific rendering (underwater, caustics, reflections, foam on the world surface), use Water World Renderer instead. It extends this component with the same features as Water Surface on a per-tile Fluid Renderer.

Fluid Renderer vs Fluid World Renderer

Each Fluid Simulation can still have its own Fluid Renderer or Water Surface for local effects, debugging, or single-tile scenes. In a tiled open-world setup you typically rely on the world renderer for the visible surface and disable or omit per-tile renderers to avoid drawing the same water twice.

Use Fluid Renderer	Use Fluid World Renderer
One simulation domain	Many simulation tiles in one view
Any Render Mode (`MeshRenderer`, `DrawMesh`, `GPULOD`, HDRP Water)	`GPULOD` only
Per-tile underwater, caustics, reflections via Water Surface	Multi-tile water features via Water World Renderer

Setting up a tiled world

A typical multi-tile workflow looks like this:

Place one Fluid Simulation per region. Align tiles in the scene so their domains meet edge to edge.
On shared edges, set Side Border Settings to Neighbour and use the same Group ID so simulations stay connected. Grid Pos helps neighbour discovery; compositing itself follows each tile’s position and size in the scene.
Add a Fluid World Renderer (or Water World Renderer) to the scene. Set Surface Properties Dimension to the XZ area you want the world surface to cover.
Match Fluid Channels on the renderer and on each simulation you want included. See Fluid Channels in Setup for naming and masking.
Enable Ocean Fft Enabled and tune Ocean FFT Settings for large open-water swell. On Flow Fluid Simulation tiles, configure Ocean FFT Coupling so local shallow-water flow follows the ocean motion near coastlines.
Optionally enable Detail Waves Enabled for small ripples on top of the composited surface. These are visual only and do not affect simulation or Fluid RigidBody physics.

Up to 32 simulation tiles can be composited at once. Fluid RigidBody buoyancy works across the combined surface when a world renderer is present; single-tile setups still use Read Back Height on the simulation instead.

Which simulations are included

The renderer does not reference simulation objects directly. Any Fluid Simulation in the scene whose Fluid Channels overlap the renderer mask is drawn:

(renderer mask & simulation.fluidChannels) != 0

Use ~0 on both sides to include every channel. Use separate channel masks and separate world renderers when you want independent surfaces (for example one renderer for ocean water and another for lava).

General

Fluid World Renderer General

Property	Description
Fluid Channels	Bitmask of simulation channels included in the world atlas. A Fluid Simulation is packed when `(renderer mask & simulation.fluidChannels) != 0`. Use ~0 to include all channels, or 0 to pack nothing.
Fluid Material	The material to be used to render the fluid surface. This material is internally instantiated at runtime. The component copies the properties from the original material to the new instance, and then overrides or injects any necessary rendering requirements (e.g., shader keywords or world-atlas textures) for the fluid simulation effects to function correctly.

Mesh Rendering

Fluid World Renderer Mesh Rendering

Property	Description
Surface Properties	Properties that determine the mesh quality and the specific drawing mode of the fluid surface. This structure holds settings that control the visual fidelity and performance of the fluid surface mesh. World rendering uses `GPULOD`; set Render Properties to the XZ footprint used for GPULOD and shader sampling (see Mesh Rendering in the Inspector).
Tile Id Grid Resolution	Resolution of the world-space tile index texture (XZ) used by GPULOD and shaders to map positions to atlas tiles. Higher values improve lookup precision for large worlds at the cost of memory and sampling cost.
Debug Visualization	Different fluid debugging modes that can be used in the editor. Play Mode only. Uses shader `FluidFrenzy/Debug/SimulationData` (same family as Fluid Renderer). Height, normals, velocity (from the height/velocity atlas), UV, and LOD modes are supported for world-atlas rendering.

Detail Waves & Displacement

Fluid World Renderer Detail Waves

Property	Description
Detail Waves Enabled	Enables procedural or baked detail waves on the world surface. These ripples are purely visual and do not affect the fluid simulation, physics, or buoyancy. Configure the wave shape and motion in Detail Wave Settings.
Detail Wave Settings	Settings for procedural or baked detail waves on the fluid surface. See Detail Wave Effect and the Detail Wave Generator at `Window > Fluid Frenzy > Detail Wave Generator` for baking static textures or flipbooks.

Ocean FFT (cascaded)

Fluid World Renderer Ocean FFT

Property	Description
Ocean Fft Enabled	Enables cascaded ocean FFT displacement (JONSWAP spectrum) on the world surface. When enabled, the renderer selects global cascade-count shader keywords and binds FFT data via shader globals. Tune spectrum and cascades in `Ocean Fft Settings`.
Ocean Fft Settings	Settings for the cascaded ocean FFT generator used when `Ocean Fft Enabled` is true. Authoring data for FFT Generator; mirrors the ocean FFT fields used on sample open-water content.

Water World Renderer

Extension of Fluid World Renderer for multi-tile water: foam, underwater, caustics, and planar reflections, mirroring Water Surface on Fluid Renderer.

Underwater Effects

Water World Renderer Underwater

Property	Description
Under Water Enabled	Controls whether the Underwater Effect is currently enabled.
Under Water Settings	Settings for all configurable visual parameters of the Underwater Effect. Defines how light interacts with the water volume, including absorption rates, scattering colors, and the appearance of the surface meniscus.

Caustics

Water World Renderer Caustics

Property	Description
Caustics Enabled	Controls whether the Caustics Effect is currently enabled.
Caustics Settings	Settings for the Caustics Effect, which renders animated light patterns projected onto the scene geometry underwater.

Surface Reflections

Water World Renderer Surface Reflections

Property	Description
Reflections Enabled	Controls whether real-time planar reflections are generated for this water surface.
Reflection Settings	Settings for the Surface Reflections module (Planar Reflections).

Ocean FFT Settings

Settings for the cascaded ocean FFT on Fluid World Renderer when Ocean Fft Enabled is true. These control the JONSWAP spectrum, cascade layers, and distance fades used for large-scale open-water displacement. To apply that motion on the shallow-water solver, configure Ocean FFT Coupling on each Flow Fluid Simulation tile.

Fluid World Renderer Ocean FFT

Property	Description
Water Preset	A starting profile for the ocean waves. Pick a preset for quick results, or choose Custom and tune the fields yourself. Changing spectrum or cascade values switches back to Custom.
Resolution	Internal resolution of each wave layer. Higher values look sharper but use more GPU memory and time.
Cascade Count	How many wave size layers are active. C1 is the largest, longest waves. More layers add detail but cost more. Inactive layers are ignored at runtime.
Wind Speed	Wind speed in meters per second. Stronger wind builds taller, faster-moving waves.
Scales	World size in meters for each wave layer (C1-C4). C1 covers the largest area (open-ocean swell). Smaller values on later cascades add nearby chop and ripples.
Choppiness	Horizontal curling of each wave layer. Higher values make crests sharper and more displaced. Values are capped to avoid broken-looking folds.
Intensities	Height of each wave layer. Scales how tall each cascade moves the surface up and down.
Speeds	Animation speed of each wave layer. Multiplier on how fast each cascade moves over time.
Wind Direction	Wind direction in degrees. Controls which way the generated waves prefer to travel.
Fetch	How far the wind has blown over open water, in meters. Larger fetch builds longer, more developed swell. Use smaller values for bays, lakes, and rivers.
Spread Blend	Blend between wind chop and organized swell direction. Lower values spread waves in more directions. Higher values align waves with the wind.
Swell	Amount of long, rolling swell. Adds slower, larger motion on top of wind-driven waves.
Peak Enhancement	How peaked the largest waves are. Higher values sharpen wave crests in the spectrum.
Short Waves Fade	Softening of the smallest ripples. Reduces high-frequency shimmer. Raise slightly if the surface looks too noisy.
Depth	Average water depth in meters. Shallow water shortens wavelengths and changes wave shape. Use a low value near shores and rivers.
Generation Threshold	How much wave folding is needed before whitecaps appear. Lower values show foam on milder crests. Higher values require stronger breaking.
Generation Amount	Strength of fresh foam at breaking crests. Higher values inject foam faster where waves are actively breaking.
Dissipation Speed	How quickly existing foam fades away. Higher values remove foam faster once waves stop breaking.
Falloff Speed	How much leftover foam blends into neighboring texels. Higher values keep tighter streaks along crests. Lower values smear foam trails wider. This controls spatial spread, not fade over time.
Displacement Fade	Distance range where FFT waves fade out near the camera. X = start fading, Y = fully faded. Uses cascade distance units (not meters); finer layers fade closer than large swell.
Normal Mip Fade	Distance range where wave normals soften far from the camera. X = begin softening (meters), Y = full softening (meters). Helps distant ocean look smoother.
Normal Mip Max	Maximum softening applied to far-away wave normals. Works with Normal Mip Fade to reduce sparkly detail in the distance.
Vertical Bias	Vertical offset of the FFT ocean surface in world space. Raises or lowers the rendered ocean without moving the fluid simulation mesh. Also used when deciding if thin sim water should be hidden in favor of the ocean look.

Surface Renderer

Surface Renderer defines a interface for rendering techniques aimed at height field surfaces. Implementing classes should provide specific algorithms and methods to visualize height maps and related surface data in different graphical contexts, such as terrain or fluid fields. This interface is designed to promote extensibility, allowing developers to introduce new rendering methods as needed while adhering to a standard approach for rendering surfaces. Currently there are three classes that extend this interface.

MeshRenderer The implementation using standard Mesh Renderer Surface components.
Mesh A simpler implementation using Mesh Surface.
GPULOD An implementation using a GPU-accelerated LOD system: GPULOD Surface.

All classes implementing this interface must provide functionality to clean up resources by overriding the dipose method, ensuring that any graphics resources are properly disposed of.

Render Properties

Properties to be used to configure components that use Surface Renderer. These properties determine the mesh quality and rendering mode of the surface.

Property	Description
Render Mode	The method used for generating and rendering the fluid surface geometry. - `MeshRenderer` Uses standard GameObjects with `Mesh Renderer` components. Best for simple setups where standard object culling is sufficient. - `DrawMesh` Uses `Render Mesh` to avoid GameObject overhead. Supports GPU Instancing. - `GPULOD` Draws the surface using a GPU-accelerated LOD system. Best for large-scale oceans or lakes. - `HDRPWaterSurface` Bridges the simulation data to a Unity `HDRP Water Surface` component (Requires HDRP).
Dimension	The total world-space size (X and Z) of the rendered surface.
Mesh Resolution	The vertex resolution of the surface’s base grid mesh. For the most accurate visualization, it is recommended to match this value to the source heightmap resolution.
Mesh Blocks	The number of subdivisions (blocks) to split the rendering mesh into along the X and Z axes. Subdividing the mesh improves GPU performance by allowing the camera to cull blocks that are outside the view frustum.
Lod Resolution	The vertex resolution of individual LOD patches when using `GPULOD`.
Traverse Iterations	The number of iterations the Quadtree traversal algorithm performs per frame when using `GPULOD`. Higher values resolve the surface quality faster during camera movement but may reduce performance.
Lod Min Max	The range of allowable LOD levels, where X is the minimum level and Y is the maximum level.
Hdrp Water Surface	Configuration settings for bridging this simulation’s data to an external `HDRP Water Surface`.

Detail Wave Effect

This effect handles the small surface ripples (detail waves) for the fluid by managing GPU math for real-time waves or playing back pre-rendered textures.

detail wave effect

These ripples are purely visual and do not affect the actual fluid simulation, physics interactions, or buoyancy math. To save on GPU performance, you can bake these waves into static textures or flipbooks using the generator tool found at Window > Fluid Frenzy > Detail Wave Generator.

detail wave generator

Detail Wave Settings

Fluid World Renderer Detail Waves

Property	Description
Mode	Determines the method used to generate or display detail waves on the fluid surface. - Baked Uses a single static texture for maximum performance but lacks motion. - Flipbook Cycles through a pre-rendered texture array for smooth animation at a low GPU cost. - Dynamic Calculates procedural wave math in real-time for infinite variety at a higher performance cost.
Resolution	The pixel dimensions of the generated wave texture. Gerstner supports any power-of-two up to 1024 for bakes / dynamic. FFT snaps to 64-512 only.
Min Frequency	Defines the scale of the largest waves in the generated spectrum. Low values (1-2) create large, rolling swells. High values (5+) make the primary wave shapes much smaller and busier.
Max Frequency	Defines the scale of the smallest ripples. Low values result in a smoother surface. High values add high-frequency micro-fidget and “noise” to the water surface.
Amplitude	A global multiplier for the internal wave height math. This scales the wave spectrum before it is packed into the texture. Use this to push waves toward their maximum normalized height.
Steepness	Determines the sharpness of the wave crests. 1.0 creates smooth, hilly waves. Higher values (up to 8.0) pinch the crests into sharp, aggressive peaks.
Anisotropy	Stretches frequencies to create wind-streaks. 1 = Circular ripples, 10 = Long streaks
Random Seed	The seed used to initialize the random layout of the wave pattern. Change this to get a different visual layout using the same settings.
Animation Type	Determines if the waves bob in place or travel in direction.
Animation Speed	How fast the wave shapes change or travel. Higher values make the water look more energetic and wind-swept.
Spectrum	Gerstner sum vs JONSWAP FFT (same packed height/normal texture). FFT requires a compute shader.
Wind Direction	The direction the waves travel (Only applies to Drifting mode).	Directional Spread	Controls the alignment of wave directions. 1.0 makes waves move in all directions (chaotic). 0.1 forces waves into organized, parallel rows.
Baked Texture	The texture asset used for displacement when in Baked mode. Expected format: Alpha channel for Height, RGB channels for Normals.
Baked Texture Array	A sequence of wave frames stored as a compressed Texture2DArray.
Flipbook FPS	The speed at which the flipbook cycles through frames.
Displacement Strength	The vertical scale of the displacement applied to the surface mesh. Higher values make the waves physically taller in world space.
Normal Strength	The intensity of the small-scale lighting details. Controls the normal map strength. High values make ripples catch more light and appear rougher.
Velocity Influence	X = Minimum strength at 0 velocity. Y = Maximum strength multiplier.
Fade Distance	Distance (Start, End) in meters where detail waves fade out to prevent shimmering and tiling artifacts.
Tiling	How many times the wave pattern repeats across the surface area.
Offset	A manual offset to scroll or shift the wave pattern.
Directional Spread	Controls the alignment of wave directions. 1.0 makes waves move in all directions (chaotic). 0.1 forces waves into organized, parallel rows.

HDRP Water Surface Properties

Contains settings used to bridge the fluid simulation data to the Unity HDRP Water System.

Property	Description
Target Water Surface	The target HDRP Water System component the simulation is to be applied. (Requires HDRP package).
Amplitude	Controls the maximum amplitude of the Fluid Simulation used to encode/decode the height to/from 0-1 range
Large Current	Controls the weight that the Fluid Simulation’s velocity should be applied to the Large Current waves of the HDRP Water System.
Ripples	Controls the weight that the Fluid Simulation’s velocity should be applied to the Rupples of the HDRP Water System.
Mesh Resolution	The vertex resolution of the surface’s base grid mesh.
Dimension	The total world-space size (X and Z) of the rendered surface.
Height Scale	The scale that will be applied to the height value in the surface’s height field.
Max Height	The maximum height the surface will be. This is used for the culling bounds of the meshes.
Heightmap Mask	Specifies which channels of the heightmap to read 1 is read, 0 is ignore. The result is accumulated with the following formula: dot(heightTexel, heightmapMask)
Lod Min Max	The minimum and maximum LOD levels that can be selected for the surface. lodMinMax.x(min) lodMinMax.y(max)

Water Rendering

Water Surface

The Water Surface is an extension of the Fluid Renderer component that renders all things water like Foam Layer, Underwater Effect visuals, absorption, and scattering. It does this by assigning the active rendering layers to its surface material and using the underwater settings.

Property	Description
Under Water Enabled	Controls whether the Underwater Effect is currently enabled.
Under Water Settings	Settings for all configurable visual parameters of the Underwater Effect. This class defines how light interacts with the water volume, including absorption rates, scattering colors, and the appearance of the surface meniscus.
Caustics Enabled	Controls whether the Caustics Effect is currently enabled.
Caustics Settings	Settings for the Caustics Effect, which renders animated light patterns projected onto the scene geometry underwater.
Reflections Enabled	Controls whether real-time planar reflections are generated for this water surface.
Reflection Settings	Settings for the Surface Reflections module (Planar Reflections).

Water Shader

The FluidFrenzy/Water shader is applied to the material used by the Water Surface component. It provides a comprehensive set of material properties for creating visually appealing water.

Compatibility: This shader is compatible with both the Universal Render Pipeline (URP) and the Built-in Render Pipeline (BiRP).

Note: The High Definition Render Pipeline (HDRP) requires a separate, dedicated shader: FluidFrenzy/HDRP/Water.

Lighting

Properties controlling the illumination and shading effects.

Water Shader

Property	Description
Specular Intensity	Scales the brightness of specular highlights from the main directional light.
Sun Roughness	Controls the roughness of direct specular highlights from lights (lower = sharper highlight, higher = broader highlight).
Shadows	Enables or disables whether the water surface receives shadows.

Reflection

Properties controlling the water surface’s reflection of the environment.

Water Shader

Property	Description
Reflection Roughness	Controls how blurry reflection probes (and HDRP smoothness) appear (lower = sharper reflections, higher = blurrier reflections).
Planar Reflection	Enables or disables the use of planar reflections instead of only reflection probes.
Reflectivity Offset	Offsets the base reflectiveness of the water surface. Use this to ensure the water is reflective even at sharp viewing angles.
Distortion	Scales the distortion applied to planar reflections.

Absorption

Properties controlling depth-based color, transparency, and refraction effects.

Water Shader

Property	Description
Color	RGB sets the color of the water at maximum depth. Alpha (A) is the base transparency of the water. If ‘Refraction Mode’ is ‘Screenspace Absorb’, RGB is a color multiplier where White (1.0) is fully transparent. For ‘Alpha’ or ‘Screenspace Tint’, RGB is the final color tint the water reaches at maximum depth/opacity.
Depth Transparency	Scales the rate at which the water’s color changes and transparency fades based on depth. Lower values make the water more transparent at a faster rate.
Refraction Mode	Selects the method for rendering water transparency and refraction: - Alpha: Simple alpha blending transparency. - Opaque: Water is rendered as a solid, non-transparent surface. - Screenspace Tint: Uses screen-space refraction (GrabPass). Color interpolates from clear to the set color based on depth. Use for a single water color tint. - Screenspace Absorb: Uses screen-space refraction (GrabPass). Scene color is multiplied by water color, allowing for a color gradient (e.g., clear to turquoise to blue).
Distortion	Scales the amount of distortion applied to the screenspace refraction effect (‘Screenspace Tint’ or ‘Screenspace Absorb’ modes).

Subsurface Scattering

Properties controlling the diffusion of light and subsurface scattering effect beneath the water surface.

Water Shader

Property	Description
Color	The tint of light scattered inside the water, like underwater fog or sun through shallow waves.
Intensity	Master multiplier on all scatter terms below.
Ambient Scattering	Constant glow from ambient light across the whole surface. Needs baked GI to show on BiRP.
Height Scattering	Adds ambient glow on wave crests where the water is raised.
Displacement Scattering	Adds ambient glow where the surface is choppy or horizontally displaced.
Scattering Wave Height	Typical wave height used to scale Height and Displacement scattering. Lower values make those sliders more sensitive.
Body Scattering	How much the sun glows through flat areas and wave troughs.
Tip Scattering	How much the sun glows through wave crests. Usually the most visible of the two.
Foam Contribution	Scales the subsurface scattering contribution in areas covered by foam.

Waves

Properties for adding detail to the water surface using normal mapping and procedural vertex displacement.

Water Shader

Property	Description
Normal Map	Texture used to add fine detail to the water’s normals for lighting and PBR shading.
Velocity Influence	Min = Strength at resting water. Max = Max strength multiplier at high velocity.

Foam

Properties controlling the appearance and masking of the foam effect.

Water Shader

Property	Description
Foam Color	Sets the Foam Color (RGB) and acts as a multiplier/mask (A) for the Foam Map’s transparency.
Foam Map	Texture used for the foam’s diffuse color (RGB) and its base mask/transparency (A).
Foam Normal Map	Normal map texture used to add PBR lighting detail to the foam.
Foam Visibility Range	Sets the minimum and maximum threshold values for when the foam becomes visible and reaches its maximum strength. Foam visibility is interpolated between these values using a smoothstep function.
Screenspace Particles	Enables the use of the screenspace particles (from the FluidParticles component) as an additional mask to generate foam.
Foam Mode	Selects the blending method for the foam: • Albedo: Soft foam using the Foam Map for color and mask. • Clip: Hard-edged foam using the Foam Map’s red channel as a clip value for sharp borders. • Mask: Uses the Foam Layer Mask’s value to select one of the Foam Map’s RGB channels as an extra mask for blending the foam color, allowing for varied intensity: 0-0.334 uses Blue, 0.334-0.667 uses Green, and 0.667-1 uses Red.
Foam Smoothness	Controls how glossy the foam appears. Lower values produce matte, chalky whitecaps.
Water Specular Suppress	Lowers water smoothness (sun spec + reflections) on visible foam. 1 = matte foam smoothness, 0 = no change.
Foam Ambient Floor	Minimum brightness for foam in shadowed areas.

Rendering

General rendering, depth-handling, and simulation sampling properties.

Water Shader

Property	Description
Layer	Selects which layer (e.g., Water or Lava, etc.) from the Fluid Simulation field to sample for effects.
Fade Height	The world height at which the water will be fully faded out. Used to soften edges or blend with geometry above a certain height.
Linear Clip Offset	A linear offset applied to the clip-space Z depth to help prevent visual clipping (Z-fighting) with close terrain or surfaces.
Exponential Clip Offset	An exponential/depth-based offset applied to the clip-space Z depth to help prevent visual clipping (Z-fighting) with distant terrain or surfaces.
UV Space	Controls which coordinate space is used for sampling Wave Normal / Foam / Detail Waves. - Normalized UV Space: uses simulation UVs in 0..1. - World UV Space: uses world XZ planar UVs. In this mode the texture tiling values are interpreted as repeats per meter (1,1 repeats every meter).
Non-Tiled Sampling	Hides texture tiling artifacts on the wave normal, detail waves and foam by sampling a noise key once and offsetting samples. Slight extra cost.

Underwater Effect

The Underwater Effect module renders the visuals you see when the camera goes underwater. It is supported in all render pipelines.

It uses the same simulation math as the water surface to ensure the underwater volume matches the waves perfectly. However it has its own independent visual settings, allowing you to style the underwater atmosphere separately from the surface itself.

This distinction is useful for gameplay as you can make the underwater view clearer or brighter than the surface to help players see further. The effect handles features like light absorption, fog scattering, and directional lighting to create the underwater atmosphere.

Underwater Settings

Water World Renderer Underwater

Settings for all configurable visual parameters of the Underwater Effect. This class defines how light interacts with the water volume, including absorption rates, scattering colors, and the appearance of the surface meniscus.

Absorption

Property	Description
Color	The base transmission color of the water. This defines the color of the water as light passes through it. Brighter colors make the water look clear, while darker colors make the water look thick and deep. This works with the absorption depth scale to decide how much the scene behind the water is tinted.
Absorption Depth Scale	Controls the rate at which light is absorbed as it travels through the water. Higher values result in darker water where light cannot penetrate as deeply. This scaling factor applies to the exponential decay of the `Water Color`.
Absorption Limits	Clamps the calculated absorption to a specific range (Min, Max). Useful for preventing the water from becoming completely black at extreme depths or ensuring a minimum amount of visibility.
Color	The color of the light scattered within the water volume (subsurface scattering/fog color). Defines the color of the fog when light illuminates the water. Usually a bright cyan or teal for tropical water, or a murky green/brown for swamps.
Ambient Intensity	The base ambient contribution to the scattering effect, independent of direct lighting. Higher values cause the underwater fog to glow brightly even in shadows or when facing away from the sun. Lower values rely purely on direct sunlight for illumination.
Total Intensity	A global multiplier for the overall scattering intensity. Higher values create a dense, opaque volumetric fog. Lower values make the scattering very subtle, preserving the clarity of the absorption color.

Meniscus(Water Line)

Property	Description
Meniscus Thickness	The vertical thickness of the meniscus line on the camera lens (in centimeters). Simulates water clinging to the camera glass. Higher values create a thicker, more prominent droplet band at the waterline. Set to 0 to completely disable the meniscus effect.
Darkness	Controls the intensity/darkness of the meniscus line effect. Low values give the band a subtle, colorful tint matching the water color. High values simulate a physically thick droplet that blocks incoming light, creating a dark rim.
Refraction Bulge	Controls the refraction strength (optical distortion) of the meniscus droplet. Higher values bend the background pixels (Snell’s Law), causing extreme lensing and total internal reflection at the edges. Lower values look like flat, undisrupted glass, Negative values intert the refraction.
Reflectivity	The base reflectivity (Fresnel R0) of the wet meniscus lens. Higher values make the droplet highly reflective (mirror-like), reflecting more of the skybox/environment probe. Lower values keep the droplet mostly transparent.
Specular Intensity	Controls the brightness of the directional light specular glint on the meniscus. Higher values create a bright sun highlight when the camera looks towards the directional light at the waterline. Lower values dull the highlight.
Specular Power	Controls the sharpness and focus of the specular glint on the meniscus. Lower values (e.g., 16-64) spread the sun’s reflection out into a wide, wet smear across the lens. Higher values (e.g., 256-512) tighten the highlight into a microscopic, sharp pinpoint.
Chromatic Dispersion	Splits the RGB light (chromatic aberration) when refracting through the meniscus droplet. When enabled, the droplet samples three slightly different indices of refraction, causing a prismatic rainbow fringing effect at the edges of the water band.

Scattering (Fog)

Property	Description
Body Scattering	Sun scatter on flat wave troughs.
Tip Scattering	Sun scatter on wave crests.
Height Scattering	Ambient height term scale (matches surface Height Scattering).
Displacement Scattering	Ambient chop term scale (matches surface Displacement Scattering).
Scattering Wave Height	Reference wave height for ambient scatter terms (matches surface Scattering Wave Height).

Caustics Effect

Caustics is an option on the Water Surface that simulates the shifting light patterns projected onto the seafloor and submerged objects.

alt text

To keep performance high, the system uses a fast approximation rather than trying to calculate physically accurate light paths. It combines an animated texture sequence with procedural highlights that are tied to the surface wave curvature, ensuring the light patterns always match the motion of the water above.

The effect works directly with the Fluid Simulation, meaning it uses the same flow mapping as the surface itself. If the water is flowing or swirling, the caustics will follow that same movement. You can also enable triplanar projection to prevent the patterns from stretching or smearing on vertical surfaces like underwater cliffs or steep walls.

It also accounts for surface conditions for example, Foam Masking can be used to soften or dim the light patterns in areas where thick foam would naturally scatter the light. To keep transitions smooth, the effect uses depth fading to blend the patterns in and out based on how far they are from the surface, preventing them from looking too sharp at the shoreline or in very deep water.

Caustics Settings

Water World Renderer Caustics

Settings for all configurable visual parameters of the Caustics Effect. This class defines animated light patterns projected underwater, wave-driven highlights, and global visibility attenuation.

Texture Projection

You can use these settings to customize the look of the animated texture patterns, including how fast they move, how they warp with the waves, and whether they use triplanar mapping to stay consistent on vertical walls.

Property	Description
Animation FPS	The playback speed of the animated caustics texture sequence. Defines how many frames per second the texture advances. Higher values result in faster, smoother motion.
Tiling	Controls the scale of the projected caustics pattern. Higher values increase the tiling frequency, making the pattern appear smaller and more dense across the environment.
Triplanar Projection	Enables triplanar projection to prevent texture stretching on vertical surfaces. Projects the texture from three orthogonal axes (X, Y, Z) instead of a single top-down projection. Essential for maintaining pattern consistency on cliffs, walls, and steep underwater terrain.
Wave UV Distortion	The strength of the UV distortion applied to the caustics based on surface wave normals. Simulates refractive warping by shifting the texture coordinates relative to the waves above.
Texture Intensity	The brightness multiplier for the projected caustics texture. An independent scalar specifically for the animated texture component of the effect. Zero disables the Fluid Render Pipeline shader variant (no flipbook samples).
Channel Mask	Defines which texture color channels contribute to the final caustics pattern. Useful for isolating specific channels in packed textures.
Chromatic Aberration	The strength of the color splitting effect at the edges of the caustics. Simulates light dispersion (prismatic effect), creating rainbow-like fringing around high-contrast areas of the pattern.

Wave Highlights

These properties control procedural glints calculated directly from the surface waves, allowing you to adjust the intensity and sharpness of the light streaks hitting the seafloor.

Property	Description
Wave Intensity	The brightness of the procedural glints generated by surface wave curvature. Unlike the texture projection, these highlights are calculated analytically from wave refraction to provide a direct link between the surface and the seafloor.
Wave Sharpness	Controls the focus and size of the procedural wave highlights. Higher values result in sharper, thinner glints (lensing effect), while lower values create broader, softer highlights.

Global Settings

This section handles the overall strength and blending of the effect, including how it reacts to shadows and foam, and how it fades out as the water depth increases.

Property	Description
Global Intensity	A multiplier for all caustic lighting contributions. Scales both the texture projection and the procedural wave highlights simultaneously.
Darkness	Controls how much the sea floor is darkened in the areas between light patterns. Increasing this value darkens the “caustic shadows,” making the bright light patterns appear more high-contrast and prominent.
Shadow Intensity	Controls the visibility of caustics within areas shadowed by external light sources. A value of 0 makes caustics completely invisible in shadow, while a value of 1 allows them to remain fully visible.
Surface Fade-In	Defines the depth range near the surface where the caustics begin to appear. The X value represents the depth where the effect starts, and the Y value is where it reaches full intensity. This prevents visual “popping” at the water line.
Depth Fade-Out	Defines the depth range where the caustics gradually disappear as light is absorbed. The X value is the depth where fading begins, and the Y value is the depth where caustics are completely extinguished.
Foam Masking	Controls how much surface foam occludes the caustics on the seafloor. Simulates the diffusive nature of bubbles. Thick foam scatters light, preventing sharp caustics from forming and casting a soft shadow on the environment below.
Half Resolution	Renders caustics at half screen resolution and upsamples before compositing. Large GPU win; slightly softer patterns.