Physical Water Surface

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Approved for Versions:4.10, 4.11, 4.12, 4.13, 4.14, 4.15, 4.16, 4.17

Overview

Physical Water Surface is an easy to use and physically correct water shader with great runtime performance. It features a large database of wave spectra for different sea states, an automatic buoyancy system, seamless sea state transitions and extensive documentation.

Physical Water Surface is available here on the UE4 Marketplace

PhysicalWaterSurface DemoMap.gif

  • Realistic water motion: A Gerstner Waves implementation using physically correct wave spectra
  • Adaptive sea state: Water motion adapts to selected wind speed (1 m/s to 35 m/s) and fetch length (50 km to 1500 km)
  • Seamless Stea State Transitions: Beautiful and completely smooth transitions between different sea states
  • High quality buoyancy system: Physically accurate buoyancy that sets up automatically. Floating objects can fully interact with the UE4 physics system
  • Great performance: Buoyancy is implemented in Blueprint and can be automatically nativized to C++ code (verified to work with 4.14 and higher)
  • Infinite Ocean System: The water plane translates and scales with the camera, creating the impression of an infinite ocean
  • Water Material tiles infinitely: Use the supplied water plane mesh, or apply the water material to your own mesh
  • Six example maps are included that show how all the different features work, making your first steps easy
  • A player controlled boat is included to get you started
  • NavMesh is supported and builds on the water plane
  • Compatible with Orbit Weather and Seasons
  • Complete and and extensive documentation available online before purchase (on this page)

Note Please don't forget to rate Physical Water Surface on the Marketplace page, your feedback is very appreciated!

Link to support thread in the forum

Video Gallery

Watch all videos on my YouTube channel!

Getting Started

Physical Water Surface 200px play.jpg

Watch this short video to get started with Physical Water Surface. The video shows:

  • How to add the water surface to an empty level
  • How to add a mesh from the Content Browser and make it float
  • How to change wind speed and fetch length

Check out the demo maps that are included in the pack:

  • DemoMap is the scene from this video demonstrating buoyancy for simple and complex objects
  • AltArtStyle is the scene from this video featuring a different water look with SSR, a quiet ocean and a floating box
  • SeaStateTransitionsDemo is the scene from this video showing seamless transitions between different sea states
  • WindSpeedsDemo is the scene from this video showing different sea states depending on the selected wind speed and fetch length
  • SteerableBoat is a map that shows how to set up a player controlled boat. The boat is controlled with the WASD keys, the space bar can be used to jump out of the water. The boat can interact with other objects that have simulate physics enabled.
  • ManualPoints: This map demonstrates the use of the Buoyancy Mode "Manual Points" that allows manually defining the points for buoyancy calculation.

Physical Water Surface comes with a ready to use WaterPlane Blueprint and a Buoyancy Component that makes objects float. The WaterSettings Blueprint controls the look of the waves.

Blueprints and Buoyancy Component

How To Add Water To A Map

WaterSettings Blueprint Details Panel

First, add a WaterSettings Blueprint to your level. This Blueprint manages the database of wave spectra and automatically writes the material parameters to the water material. You always need exactly one WaterSettings Blueprint in your level.

Next, add one or multiple WaterPlane Blueprints. You now have a working water surface! If you started with the default empty level, you should also add a SkyLight and a PostProcessVolume with FXAA enabled and Unbound set to true. If you are using 4.14 or higher, you need to manually select FXAA under Project SettingsRenderingAnti-Aliasing Method.

By default, the sea state is set to a Wind Speed of 10 m/s and a Fetch Length of 50 km. To change the sea state, just select different values in the Details panel of the WaterSettings Blueprint. Of course, you can also change these values from another Blueprint.

WaterPlane Blueprint Details Panel

If the Follow Camera option in the WaterPlane Blueprint Details panel is set to true, the WaterPlane is automatically translated and scaled to create the impression of an infinite ocean. If you are creating a lake it's better to turn this option off and to create a custom water plane mesh with exactly the right size. If you enable this option, it's a good idea to check in Wireframe view mode if the automated scaling of the water plane works as intended.

Physical Water Surface comes with three different Material Instances that derive from the Water material:

  • WaterInstance
  • WaterInstanceShiny
  • WaterInstanceAlternative

To change the water material, select a different Material Instance in the Details panel of the WaterPlane Blueprint in your level. To tweak the look of the water surface, change the parameters of the Material Instance. Ignore all the Vector Parameters starting with R... and W..., they are automatically set by the WaterSettings Blueprint.

Water Material and Material Instances

Lighting The Water Surface

The look of the water surface is heavily influenced by the surroundings, be it a sky sphere for an infinite ocean or the adjacent landscape of a lake. This is particularly true if you have a very reflective water material. In most of my demo videos there ist just a sky sphere and no other surrounding geometry, so I enabled the foam texture and the detail normal map to make the water surface look more interesting. A different approach is to make the water surface more reflective and to add Reflection Capture Actors and have the look of the water be dominated by reflections. A good example for this water look is the Vehicle Game example from Epic (see also the tutorial below).

Basic Lighting Setup

To get started with lighting, check out the demo Maps that are included. Here's the basic lighting setup that is used:

  • Use the Sky Sphere and Light Source from the Default empty map.
  • Change the Sun Brightness and the rotation of the directional Light Source to your liking.
  • Add a Sky Light with Source Type SLS Captured Scene. This will light the water surface and the floating objects from all directions.
  • Add a Lightmass Importance Volume and scale it up, for example by factor 50. In the Viewport, use the ShowVizualizeVolume Lighting Samples option to make sure you have more than one sample in the volume. Lighting Samples usually are created in great number only above static surfaces, but the water surface is set to movable because of the Infinite Ocean System. When we make the Lightmass Importance Volume large enough, the engine will create some Lighting Samples scattered in the Volume. These are enough to light objects that are floating on the surface, even outside the bounds of the Volume.

Making An Object Float With The Buoyancy Component

Buoyancy is implemented as a Blueprint Component that can be added to any Static or Skeletal Mesh. To use it, follow these steps:

  1. Set the Mobility of the Mesh to Movable. Dont skip this step!
  2. Click the Add Component button in the Details panel of your mesh and select the Buoyancy Component. The Buoycancy Component will appear in the Details panel.
  3. Click the Buoyancy Component in the Details panel and choose a Buoyancy Mode: Single Points, Auto Points and Manual Points are available. If you're using Auto Points, you can use the additional settings below to tweak the buoyancy motion.
  4. Hit Play to view the Buoyancy in action. If you click Simulate, the floating objects and the water surface will appear to be out of sync because the time nodes in the material and in Blueprint give different values in this case.
Buoyancy Component settings for a cube

In SinglePoint Mode, the floating object will be fixed to a single point on the water surface. The translation and rotation of the object are directly taken from the output of the Gerstner equations, so all the other settings on the Buyancy Component have no effect. As a result, the object will just move with the water surface and rotate according to the local normal vector of the point on the water surface where it is located. This buoyancy mode is relatively cheap to calculate because the Gerstner equations need only to be evaluated at one point for each tick. However, the motion of the object will only be realistic for small objects, for example leaves or rubber ducks floating on the surface. For large objects like boats, you should use AutoPoints mode.

In AutoPoints mode, a Physics Simulation is performed. The buyant force on a number of points on the object is calculated and applied. The magnitude of the buoyant force depends on the depth of immersion of each point. The counteracting force is gravity that is automatically applied by the engine. The Buoyancy Component will automatically generate the coordinates for the points in rectangular or elliptical shape, taking into account the dimensions of the object. With the N Points X and N Points Y you can control the number of points that are generated. In elliptical mode, N Points X is the number of points in radial direction and N Points Y is the number of points in tangential direction. The buoyant force is scaled so that at a certain depth of immersion, an equilibrium exists. You can change how deep an object is submerged with the Float Factor parameter.

In the image on the right you can see the Buoyancy settings used for the large floating cubes in the DemoMap that is included in the Physical Water Surface package. Rectangular Buoyancy Mode is obviously a good choice for cubes. Setting the number of points in X and Y direction to two will generate four points at the corners of the box.

Buoyant Force Debug Visualization on a Boat

To check the location of the calculated points, you can enable the Draw Debug option. In this mode, a small sphere is drawn at the coordinates of each points, and the length of the vertical arrows is proportional to the buoyant force. Use this mode to make sure that the number and shape of the generated points is as intended.

If you set up Buoyancy for large objects that need to move in a certain way, you will probably need to tweak the parameters a bit to get the desired result. As an example, have a look at the parameters used for the boat in the DemoMap. With the PointsScale parameter (by default set to 0.8) you can scale the coordinates of the generated points inwards so that no points are located directly at the bounds of the object. This is usually desirable.

For the cubes, we have generated only four points. With PointsScale set to 1, these four points would be located exactly at the corners of the cube. This way, the buoyant force that exists at the center of the cube would be neglected completely. By scaling the points inwards a bit, we move them closer to the center. The hull of boats is usually bent, and with PointsScale set to 1 the outmost generated points would end up outside of the hull, where no buoyant force exists. It may also be necessary to adjust the Linear Damping and Angular Damping parameters, especially of you're dealing with very large or very small objects.

Note Make sure to enable the Nativize Blueprint Assets option that converts all Blueprints to C++. If you get an error while packaging, please read this answer

The Buoyancy calculations are done in Blueprint on the CPU, so it is important to keep an eye on CPU performance. You can use the N Points Per Frame and N Frames Pause parameters on the Buoyancy Component to improve performance. With the N Points Per Frame parameter you can limit the number of points that are updated each tick with the Gerstner equations. For the remaining points, the depth is updated with linear extrapolation from the last known values, which is much cheaper to calculate. To update all points each Tick with Gerstner equations, set N Points Per Frame to (N Points X) * (N Points Y). With N Frames Pause set to 1, Gerstner calculations will only be performed every other Tick, if you set it to 2 only every third Tick and so on. To disable the pausing, set N Frames Pause to 0.

Points in 3D space defined with Manual Points mode

Manual Points mode allows to manually define the points used for buoyancy calculation. The automatically created points in Auto Points Mode are always generated in a plane. This prevents the floating object from flipping upside down in most cases. However, sometimes you want an object to rotate freely, for example a floating box that is smashed around by the waves.

In Manual Points Buoyancy mode you can define the coordinates of the points that are used for the buoyancy calculation yourself. You can set the values in the Details panel, or from another Blueprint. Enter the coordinates in local object space. For an example, have a look at the demo map ManualPoints that is included with Physical Water Surface.

Seamless Sea State Transitions

Physical Water Surface can do seamless sea state changes. This means that during runtime the wave parameters are manipulated in such a way that a seamless transition to a new sea state (defined by a new wind speed and fetch length) is achieved in a given time. Watch this video to get an impression how the transitions look like:

The map that was used to create this video is included with Physical Water Surface, it is named SeaStateTransitionsDemo. Have a look in the Blueprint BP_TransitionsDemo in this map to see how the sea state transitions are triggered.

To trigger a sea state transition, call the ChangeSeaState function of the WaterSettings Blueprint. The input arguments are the target wind speed, target fetch length and the time allotted for the transition.

Triggering a seamless sea state transition

If the new values for wind speed and fetch length are very different, it is advisable to to get there with multiple small steps, meaning multiple consecutive calls to the ChangeSeaState function that each change the sea state just a bit. This way the transition will look more natural because the algorithm only needs to figure out a good transition for values that are not too different.

The minimum TransitionTime that should be used depends on how much wind speed and fetch length are changing. As you can see in the video above, in some cases 10 seconds are enough to get a nice-looking transition. However if you can, you should use higher values to make the transition look more natural.

The Delay node shown in the screenshot is optional. Use it if you want to delay execution of the subsequent code until the transition has finished.

Setting Up A Player Controlled Boat

The SteerableBoat map that is included with Physical Water Surface shows how to set up a player controlled boat. The boat is controlled with the WASD keys, the space bar can be used to jump out of the water. The boat can interact with other objects that have simulate physics and collision enabled. Everything is set up in the PawnBoat Blueprint. You can use this Blueprint as a starting point for your player controlled boat. Never try to set the location or rotation of the boat directly. Instead, use the Add Force/Torque/Impulse at Location Blueprint nodes.

Querying The Wave Height From Blueprint

If you turn to the right in the DemoMap, you will discover three small Blueprints floating in the water. These are example Blueprints that show you how to query the height and speed of the water surface.

Querying the location of a point on the water surface

The WaterLocation Blueprint shows how to query the location of a point on the water surface, given the coordinates (X,Y) of the initial position. Just call the function Calculate Delta Only of the WaterSettings Blueprint with (X,Y) as input, and the 3D delta vector with the shift is returned. If you also need the normal vector calculated, call the function Calculate Delta Normal instead.

The WaterHeight blueprint calculates the wave height at a fixed point (X,Y). In this case, it is necessary to store the Delta value from the last tick in a variable.

The WaterSpeed Blueprint calculates the vertical speed of the water surface at a point (X,Y) and displays an arrow proportional to the speed.

Compatibility with Orbit Weather and Seasons

I've collaborated with the developer of Orbit Weather and Seasons to make his weather system and Physical Water Surface compatible. With this compatibility, changing the cloud density will automatically also trigger a sea state transition if you use both systems together. For detailed information, see this separate wiki page.

FAQ

Which engine versions are compatible?

Currently Physical Water Surface is developed in 4.10 and has been tested successfully with versions 4.10 to 4.17. If you are using 4.14 or higher, please make sure to read the information about Temporal AA below. If your water plane is gray after updating to 4.17 you can read below how to fix it.

The water surface looks blurry when I use Temporal AA

If you have fine detail on the water surface, for example a fine normal map or a foam texture, FXAA tends to look better than Temporal AA. For this reason, most of my demo videos were created using FXAA. If you want to use Temporal AA, you should set Project SettingsEngineRenderingAccurate velocities from Vertex Deformation to true. This way, the water surface displacement will be properly taken into account for Temporal AA. If you are using an engine version between 4.10 and 4.13, you will find that FXAA is enabled in the PostProcessVolume that comes with the demo maps. If you are using 4.14 or higher, you need to manually select FXAA under Project SettingsRenderingAnti-Aliasing Method. Beginning in 4.14, the Anti-Aliasing Method setting is no longer part of the PostProcessVolume settings, so it will be Temporal AA by default. Also, keep in mind that the Anti-Aliasing Method can change to Temporal AA when you update your project to 4.14.

The water surface is gray and is not moving in engine version 4.17

If you encounter this behavior after updating your project to 4.17, here is how to easily fix it. Open the Construction Script of the WaterPlane Blueprint and add a Make Literal Bool node that is set to True and connect it to the Update Wave Parameters node. After compiling and saving this Blueprint, the water will be visible again. It seems that there is a bug in 4.17 that changes the default value from True to False, and adding the Make Literal Bool node fixes that.

Add a Make Literal Bool node like this
Can I scale the water plane to adjust the size of the waves to the scale of my game?

The water equations are implemented under the assumption that one Unreal Unit (UU) is equal to one centimeter. If the objects in your game have a different scale, the size and speed of the waves will not be correct. You can't just scale the water plane because the shape of the waves is determined by equations, independent of the object scaling. In fact, the Infinite Ocean System (if enabled) is constantly scaling the water plane up and down depending on the camera height.

Floating objects are not lit correctly

Since floating objects are moving, they can only be lit by dynamic lighting. Make sure you have a Lightmass Importance Volume that is large enough so that multiple Volume Lighting Samples are created inside the volume. It's a good idea to use the ShowVizualizeVolume Lighting Samples option in the Viewport to make sure you have more than one sample in the volume.

In my tests, one Volume Lighting Sample inside a small Lightmass Importance Volume caused incorrect lighting. When I increased the size of the volume so that multiple samples appeared the lighting was correct. You don't need the Lightmass Importance Volume to cover the whole ocean because it will extrapolate the lighting outside of the volume.

I see flickering or artifacts on the water surface

This is known to happen when World Position Offset is used to move the vertices of an object outside of the object bounds. The problem is that for a flat water plane mesh, the engine assumes that the bounds have close to zero vertical thickness. When World Position Offset is used to create waves, the vertices are moved far outside the bounds, leading to visual artifacts in some cases.

The solution is to increase the RenderingBounds Scale value in the options of the water plane Static Mesh until the artifacts disappear as described here. For a completely flat plane, you will need to put in a very high value. For this reason, the water plane Static Mesh that is included has a single out of plane face so that the engine calculates a higher thickness for the Static Mesh. With this Static Mesh, setting the Bounds Scale value to 10 is sufficient to prevent any artifacts.

In the demo maps that are included, this is all set up correctly and no visual artifacts should appear. If you create your own water plane Static Mesh, take care to set the Bounds Scale option to a high enough value. Enable the ShowAdvancedBounds option to make sure the bounds are large enough to contain the waves.

How do I enable SSR?

Actually, SSR are enabled by default, but Depending on the settings in the Water Material Instance and the lighting conditions, the SSR might not be visible. Check out the AltArtStyle demo map where the SSR are clearly visible.

How is the performance?

I did performance tests on an AMD HD 6870 graphics card with the DemoMap as Standalone Game with Smooth Frame Rate disabled, in fullscreen (Full HD) and Epic Scalability Settings. Here are the results:

  • FoamNoise set to false and no buoyancy: 101 fps
  • FoamNoise set to false and buoyancy: 94 fps
  • FoamNoise set to true and no buoyancy: 80 fps
  • FoamNoise set to true and buoyancy: 78 fps

For this test, the Buoyancy Blueprints were not converted to C++ code (which would increase CPU performance).

The material stats are:

  • Info Base pass shader with static lighting: 1565 instructions
  • Info Base pass shader with only dynamic lighting: 1533 instructions
  • Info Vertex shader: 1235 instructions
  • Info Texture samplers: 7/16
Does it contain C++ code?

No, everything is done in Blueprint.

Can I use the Nativize Blueprint Assets option when packaging to convert all Blueprints to C++ code?

Yes, this is supported and has been verified to work with engine version 4.14 and higher. You should enable this option when packaging your project for a significant increase in buoyancy performance. If you get an error when packaging with this option enabled, please see the next question.

I get an error when packaging with the Nativize Blueprint Assets option enabled

Update 2 of Physical Water Surfaced fixed a small bug that prevented successful packaging with Blueprint Nativization enabled. If you need to apply this bugfix to your project, here is how:

Open the WaterPlane Blueprint and search for the "Clamp (float)" Node. Change the Max value from 1e100000 to 1e10.

How can I make the water transparent?

Currently, the water material is not transparent. This will probably change in a future version of Physical Water Surface. In the mean time, you can try to modify the water yourself material to make it transparent.

Is the water motion deterministic?

By default, the water motion is identical every time the game starts. To get a different water motion every time the game starts, set the Random Phase Seed variable of the WaterSettings Blueprint to a random value when the game starts.

What about networking and replication?

The state of the water surface only depends on the game time, so only the time needs to be replicated to create an identical ocean for all players.

Can I use NavMesh to create an AI controlled boat?

Yes, the WaterPlane Blueprint that comes with Physical Water Surface supports NavMesh. If you place a Nav Mesh Bounds Volume in the map, NavMesh will build on the water surface. Implementing AI for a boat is very similar to AI for a car, so this tutorial can be helpful.

NavMesh building on the water surface
Does Physical Water Surface work in VR?

I've tested Physical Water Surface in VR using an Oculus Rift. Everything worked fine, the water motion looks great in VR. I suggest you try out the DemoMap using the VR Preview in the editor.

Blueprint Documentation

Note Make sure to enable the Nativize Blueprint Assets option that converts all Blueprints to C++. If you get an error while packaging, please read this answer

WaterSettings Blueprint

WaterSettings Blueprint Parameters

The WaterSettings Blueprint manages the database of wave spectra and automatically writes the material parameters to the water material instances. You always need exactly one WaterSettings Blueprint in your level.

Wind Speed: Select the wind speed you want (in m/s) and the corresponding wave spectrum will be applied automatically. Possible values are 1, 2, 3, 4, 5, 6, 7, 10, 15, 20, 25, 30 and 35 m/s.

Fetch Length: Select the fetch length you want (in km) and the corresponding wave spectrum will be applied automatically. Possible values are 50, 100, 300, 500, 750, 1000 and 1500 km.

Random Phase Seed: Random Seed for the water motion. Change this value to get a different random water motion when the game starts.

Watch this video to see some of the different sea states that are possible.

Debug: Draw debug messages on screen.

WaterPlane Blueprint

WaterPlane Blueprint Parameters

You can add one or multiple WaterPlane Blueprints to your level. The WaterSettings Blueprint will find them automatically and write the Gerstner Wave Material Parameters to the Dynamic Material Instances of the WaterPlanes.

Material Instance: Here you can change the Water Material Instance that is used. By default it is set to WaterInstanceShiny.

RefreshMaterial: Clicking this checkbox just causes the Construction Script of the Blueprint to be executed again. This sometimes helps if the water material does not update for some reason.

Follow Camera: Enables or disables the Infinite Ocean System. If set to true, the water plane is translated and scaled to create the impression of an infinite ocean. For lakes or other small water surfaces, it is better to set this to false and to create a water plane mesh that matches the shape of the lake.

Height Zoom Factor: If the Infinite Ocean System is enabled, the water plane is scaled up when the camera moves upwards. This factor influences how fast the plane is scaled up.

MinimumHeight: Minimum height of the camera above water plane assumed in the calculations of the Infinite Ocean System. Prevents scaling down the water plane too much when the camera is very close to the water surface.

Buoyancy Component Blueprint

Buoyancy Component Parameters

Add this Component to any Static Mesh or Skeletal Mesh to make it float in a WaterPlane Blueprint. Don't forget to set the Mobility of the Mesh to Movable!

Buoyancy Mode: In Single Point mode the floating object is fixed to a single point on the water surface. Location and Rotation are taken directly from the coordinates and normal calculated with the Gerstner equations. This mode only looks good for small objects, but is relatively cheap to calculate. In Auto Points mode a Physics Simulation is performed. The buoyant force on a number of automatically generated points on the object is calculated and applied. The magnitude of the buoyant force depends on the depth of immersion of each point. The counteracting gravity force is automatically applied by the engine. In Manual Points mode, you can define the Points array yourself. Enter the coordinates either manually in the Details panel, or set the values from another Blueprint.

Note: the following settings only have an effect in Auto Points and Manual Points mode:

Points Shape: Defines the shape of the automatically generated points to be rectangular or elliptical. The point generation automatically takes into account the size of the mesh.

Points Scale: With this parameter (by default set to 0.8) you can scale the coordinates of the generated points inwards so that no points are located directly at the bounds of the object. For boats with a curved hull this parameters usually needs to be smaller than one to prevent points outside of the hull.

N Points X and N Points Y: Number of points that will be generated in X (or radial) and Y (or tangential) direction.

Float Height: Applies an offset to the Z coordinate of the generated points.

Points: In Auto Points mode, the coordinates of the points are set automatically. In Manual Points mode, you need to set them manually. Enter coordinates of the points in local object space, either manually in the Details panel or set the values from another Blueprint.

Draw Debug: Enables the debug visualization. The generated points visualized as points, and arrows are drawn proportional to the buoyant force.

N Points Per Frame: With this parameter you can limit the number of points that are updated each tick with the Gerstner equations. For the remaining points, the depth is updated with linear extrapolation from the last known values, which is much cheaper to calculate. To update all points each Tick with Gerstner equations, set N Points Per Frame to (N Points X) * (N Points Y) if you're using PointsShape Rectangle and to (N Points X) * (N Points Y) + 1 if you're using PointsShape Ellipse.

N Frames Pause: If this parameter is set to 1, the Gerstner calculations to update the points will only be performed every other Tick, if you set it to 2 only every third Tick and so on. To disable the pausing, set N Frames Pause to 0.

Float Factor: This parameter changes how how deep the floating object is submerged in the water.

Linear Damping and Angular Damping: The damping usually needs to be adjusted a bit for very large or very small objects.

Drag Multiplier: Floating objects also perform a subtle horizontal motion depending on the local horizontal water speed. Use this parameter to influence the horizontal drag force.

Enable Buoyancy: Enable and disable the buoyancy completely. To save CPU performance, it is a good idea to disable the buoyancy of objects that are not visible or far away. If you don't want to disable buoyancy completely, switching these objects to Single Point mode will also save some CPU performance.

Points Offset: Use this Vector2D to apply a horizontal offset to the automatically generated points.

Material Documentation

Note Ignore all the Vector Parameters starting with R... and W..., they are automatically set by the WaterSettings Blueprint

Material Instance Parameters

BlendOutNormals: If enabled, the normals are gradually lerped to be vertical at large distance. This reduces flickering that otherwise would be visible in the distance on the water surface.

FoamNoise: If enabled, the foam texture is modulated randomly so that it is not repeating any more. Enable this only if you need it, as it costs some performance.

GerstnerWaves: Here you can disable the Gerstner waves. Useful for debugging.

NoiseInvert: Inverts the noise that is used for the foam modulation. Can be useful for debugging.

DetaiNormalMapMultiplier: Scales the UVs of the detail normal map.

DetailNormalSpeed: Changes the speed of the detail normal map animation.

DetailNormalStrength: Modifies the intensity of the detail normal map. Set to 0.0 to disable the detail normal map and to get get a smooth water surface.

FoamBlendRadius: Distance at which the foam is blended out.

FoamIntensity: Influences how much foam is visible. Set to 0.0 to disable foam.

FoamMultiplier: Scales the UVs of the foam texture.

FoamSpeed: Changes the speed of the foam animation.

FresnelExponent: Exponent of the Fresnel node that is used for Base Color.

Metallic: Metallic Material Input

NoiseRotation: For foam modulation, two foam textures are scaled, rotated, and blended together. This paremeter sets the rotation angle (0-1).

NoiseSize: Influences the size of the noise that is used for modulation of the foam texture.

NormalsBlendRadius: Distance at which the normals are blended out.

NormalsStrengthDistance: This is the alpha value for blending out the value. 0.5 means that the strength of the normals is reduced by factor 0.5

RoughnessBlendRadius: Distance at which the change in Roughness occurs.

RoughnessMax and RoughnessMin: Foam has a higher roughness than water. Use these parameters to set the maximum and minimal roughness values.

SecondTextureScale: For foam modulation, two foam textures are scaled, rotated, and blended together. This parameter defines the scale of the second texture.

ColorBright and ColorDark: Changes the base color of the water surface.

FarFoamColor: When the foam is blended out, it is replaced with this color.

Tutorials

Improving an existing water material with Physical Water Surface

In this tutorial, we take the existing water material in the Vehicle Game example (available for free in the Launcher) and modify it so that the water motion is calculated with Physical Water Surface. Adding Physical Water Surface to your own project would follow a similar approach.

  1. Create a new Vehicle Game project and add Physical Water Surface.
  2. Go to Project SettingsMaps & ModesDefault Modes and set Default Pawn Class and HUD Class both to None.
  3. Create a new Camera somewhere above the water surface and set Auto Activate for Player to Player 0 in the Camera settings.
  4. Hit Play to make sure that the Camera activates and you can see the water surface.
  5. Click on the Lake Static Mesh and write down the Z Location (18110.822266 cm), then delete it from the level.
  6. Add the WaterSettings Blueprint from the Physical Water Surface folder to the level.
  7. Add the WaterPlane Blueprint from the Physical Water Surface folder to the level. In the Details panel, set the Z Location to 18110.822266 cm and set Follow Camera to false.
  8. Enable Wireframe view mode and move WaterPlane in X and Y direction until the high resolution center area of the plane is close to the camera.
  9. In the Details panel of the WaterSettings Blueprint, set Wind Speed to 1 (m/s) and Fetch Length to 50 (km).
  10. Open the M_Water_01 material that comes with Vehicle Game. Select all material nodes that are connected to the Base Color, Metallic and Roughness inputs and copy them to the clipboard (Ctrl+C).
  11. Open the Water material that comes with Physical Water Surface. Paste the nodes from the clipboard (Ctrl+V). Connect the pasted nodes to the Base Color, Metallic and Roughness inputs of the Water material, replacing the original inputs. Leave the Normal and World Position Offset connected. Save the modified Water material.
  12. Open the WaterInstanceShiny Material Instance in the Physical Water Surface folder and set DetailNormalStrength to 0.0 to get a smooth water surface.
  13. Since we have pasted the Vertex Coloer material node, you can paint foam on the water surface.
  14. You're done! You now have a water surface with the original look, but with the water motion of Physical Water Surface.
Inputs of the modified Water material