Documentation

Sky Creator for Unreal Engine 4
Available on Marketplace
Current version: 1.23

Documentation will be updated and improved over time.

Requirements

Sky Creator requires Niagara to be enabled to display some Weather FX such as rain and snow.

Depending on your needs you also might want to enable “Support Sky Atmosphere Affecting Height Fog” in Project Settings > Rendering. If set to off (by default), the atmosphere won’t affect height fog and it will be colored by Fog Inscattering Color (black by default).

Installing the Plugin (UE4)

Open Epic Games Launcher, head to Unreal Engine > Marketplace or Library tab and find Sky Creator. Press “Install to Engine” button and choose the appropriate engine version for you.

Open your project the engine version of which have the plugin already installed and head to Plugins tab. Find the Sky Creator and set it enabled by checkbox. The engine will prompt to restart itself. Restart the editor and you will have plugin enabled and ready to work.

Installing the Plugin (UE5 EA)

Since V1.03 Sky Creator supports Unreal Engine 5 Early Access. Because of engine’s Early Access state, you can’t install plugins from Epic Launcher yet, so you’ll need to copy plugin folder to your project’s folder by hand unofficially. But make sure that you’re having latest version of the plugin installed on your version of UE4. Also be sure to have Visual Studio for Unreal Engine installed otherwise you won’t be able to compile source code.

Copy from:
C:/Program Files/Epic Games/UE_4.27/Engine/Plugins/Marketplace/SkyCreatorPlugin” (or another directory where you have Unreal Engine installed
And paste to:
YourProject/Plugins/SkyCreatorPlugin”.

Next time you launch your UE5 project, the engine will prompt “The SkyCreatorPlugin was designed for build 4.2X.0 Attempt to load it anyway?”, just click yes.

P.S. Please don’t expect a flawless work with early version of UE5! This support is currently unofficial.

Quickstart

After enabling the plugin go to category Lights in a Place Mode tab. Inside there you will find a new actor Sky Creator ready to be drag’n’dropped to your scene. But before adding it make sure that you deleted or at least disabled any other Directional Light, Skylight, Volumetric Cloud and Sky Atmosphere on your level.

Now Sky Creator is ready to use. Go to Details Panel and play with settings to your liking.

To create your own Weather Preset, right click in Content Browser and select
Add/Import Content > Miscellaneous > Sky Creator Weather Preset. After that select a Sky Creator actor in your scene and drag a new weather preset onto “Editor Weather Preset” variable, making a new weather preset active. Now open it and create a new weather conditions that fits to your game if you need to.

The creative power hides exactly there. Feel free to create something awesome.

To control Sky Creator’s time of day or change weather in runtime, separate controller must be used. Most of functions are already built in such as “Realtime Time of Day” or “Lerp Weather Settings” so you don’t really need to worry about it. There are an examples of a blueprint controllers in “SkyCreatorPlugin Content/Blueprints” which you can freely use in your scenes, but you can actually use whatever you want to or create a custom controller.

How to use Weather Material FX

If you want to use Sky Creator’s Weather Material FX, you need to add “MF_SC_WeatherMaterialFX” material function to your material and re-pin Base Color, Roughness and Normal connectors through it. By default, all included effects will be enabled – Wetness, Puddles and Snow. You may optionally disable some of effects using Static Bool node and plugging it into this material function.

You may also enable Occlusion and use Distant Occlusion with it by plugging “MF_SC_DistantOcclusion” material function into the Distant Occlusion pin in “MF_SC_WeatherMaterialFX” material function. See next paragraph.

How to use Occlusion

Occlusion effect is enabled by default. It uses Scene Capture Component 2D to capture a world heightmap at a certain radius around player camera once at a defined distance step to minimize performance impact. To use Occlusion effect with Weather Material FX, you need to enable this effect by plugging Static Switch node into the Use Occlusion slot of the “MF_SC_WeatherMaterialFX” material function.

If you’re using only this, you may notice that Occlusion effect is fading after reaching capture radius. To fix this you can use “SkyCreator_CaptureDistantOcclusion” blueprint. Place it in the middle of your level, adjust the width of this capture and click Capture Heightmap. After this, Distant Occlusion heightmap will be used on the materials in the area outside of radius of main Occlusion capture.

Sky Creator Actor Settings

Here’s all settings list which is meant to be set once in editor.

General

Use Editor Time of DayControls Time of Day by Editor. Disable if using a separate controller to drive Time of Day.
Editor Time of DayTime of Day in Editor.
Use Editor Weather SettingsControls Weather Settings by Editor. Disable if using a separate controller to drive Weather Settings.
Editor Weather TypeWhether to use Editor Weather Preset or Editor Weather Settings.
Editor Weather PresetCurrent Weather Preset in Editor.
Editor Weather SettingsCurrent Weather Settings in Editor allowing to direct variable control.
Sky Creator Parameter CollectionSky Creator Material Parameter Collection. Essential for a number of effects.
Sky Sphere RadiusSky Sphere mesh radius in kilometers.
Show Debug VariablesShow or Hide debug variables across all sub-categories of settings.

Sky Atmosphere

Sky Atmosphere MobilitySky Atmosphere Mobility.
Transform Mode– Planet Top at Absolute World Position places the top ground level of the atmosphere at the world origin coordinates (0,0,0) in the scene. The Sky Atmosphere is not movable when this option is selected.
– Planet Top at Component Transform places the top ground level of the atmosphere relative to the component’s transform origin. Moving the transform of the Sky Atmosphere component, or one that it is a child of,
moves the atmosphere within the level.
– Planet Center at Component Transform places the atmosphere centered to the component’s transform origin. Moving the transform of the Sky Atmosphere component, or one that it is a child of, moves the atmosphere within the level.
Planet RadiusThe planet radius (kilometers from the center to the ground level).
Atmosphere HeightAtmosphere Height defines the height of the atmosphere above the planet’s surface (in kilometers).
Trace Sample Count ScaleScale the atmosphere tracing sample count. Quality level scalability.
The sample count is still clamped according to scalability setting to ‘r.SkyAtmosphere.SampleCountMax’ when ‘r.SkyAtmosphere.FastSkyLUT’ is 0.
The sample count is still clamped according to scalability setting to ‘r.SkyAtmosphere.FastSkyLUT.SampleCountMax’ when ‘r.SkyAtmosphere.FastSkyLUT’ is 1.
The sample count is still clamped for aerial perspective according to ‘r.SkyAtmosphere.AerialPerspectiveLUT.SampleCountMaxPerSlice’.

Volumetric Clouds

Bottom AltitudeThe altitude at which the cloud layer starts (kilometers above the ground).
Max HeightThe altitude at which the cloud layer ends (kilometers above the ground).
Tracing Start Max DistanceThe maximum distance of the volumetric surface before which we will accept to start tracing (in kilometers).
Tracing Max DistanceThe maximum distance that will be traced inside the cloud layer (in kilometers).
Per Sample Atmospheric Light TransmittanceWhether to apply atmosphere transmittance per sample, instead of using the light global transmittance.
Quality
Ground ContributionSample the shadowed lighting contribution from the ground ontro the medium (single scattering).
This adds some costs to the tracing when enabled.
Multi Scattering Approximation Octave CountHow many octave to use for the multiple-scattering approximation.
This adds some costs to the tracing. 0 means single scattering only.
View Sample Count ScaleScale the tracing sample count in primary views.
Quality level scalability CVARs affect the maximum range.
The sample count resolution is still clamped according to scalability setting to ‘r.VolumetricCloud.ViewRaySampleCountMax’.
Reflection Sample Count ScaleScale the tracing sample count in reflection views.
Quality level scalability CVARs affect the maximum range.
The sample count resolution is still clamped according to scalability setting to ‘r.VolumetricCloud.ReflectionRaySampleMaxCount’.
Shadow View Sample Count ScaleScale the shadow tracing sample count in primary views, only used with Advanced Output ray marched shadows.
Quality level scalability CVARs affect the maximum range.
The sample count resolution is still clamped according to scalability setting to ‘r.VolumetricCloud.Shadow.ViewRaySampleMaxCount’.
Shadow Reflection Sample Count ScaleScale the shadow tracing sample count in reflection views, only used with Advanced Output ray marched shadows.
Quality level scalability CVARs affect the maximum range.
The sample count resolution is still clamped according to scalability setting to ‘r.VolumetricCloud.Shadow.ReflectionRaySampleMaxCount’.
Shadow Tracing DistanceThe shadow tracing distance in kilometers, only used with Advanced Output ray marched shadows.
Low Cloud Map
Low Cloud Map ScaleLow Cloud Map tileable texture scale in kilometers.
Low Cloud Map OffsetLow Cloud Map tileable texture UV offset.
High Cloud Map
High Cloud Map ScaleHigh Cloud Map tileable texture scale in kilometers.
High Cloud Map OffsetHigh Cloud Map tileable texture UV offset.
High Cloud Horizon Fade HardnessHardness of fading High Cloud Map at horizon.
Cloud Noise
Auto ScaleAutomatic Cloud 3D Noise Scaling relative to “Low Cloud Map Scale”.
Shape Noise ScaleTileable 3D Shape Noise Scale (kilometers).
Detail Noise ScaleTileable 3D Detail Noise Scale (kilometers).

Sky Light

Sky Light MobilitySky Light Mobility.
Real Time CaptureWhen enabled, the sky will be captured and convolved to achieve dynamic diffuse and specular environment lighting.
SkyAtmosphere, VolumetricCloud Components as well as sky domes with Sky materials are taken into account.
Should be enabled if using dynamic time of day.
Lower Hemisphere Is Solid ColorWhether all distant lighting from the lower hemisphere should be set to “LowerHemisphereColor.
Enabling this is accurate when lighting a scene on a planet where the ground blocks the sky, however disabling it can be useful to approximate skylight bounce lighting (eg Movable light).

Sun Light

Sun Light MobilitySun Light Mobility.
Control Sun DirectionWhether to control Sun direction by Sky Creator.
Use TemperatureWhether to use Color temperature for sun.
Angular DiameterAngle subtended by light source in degrees (also known as angular diameter). Defaults to 0.5357 which is the angle for our sun.
Constant Atmosphere Disk Color ScaleWhether to use constant Atmosphere Disk Color Scale for Sun.
Atmosphere Disk Color ScaleA color multiplied with the sun disk luminance.
Sun Positioning
Sun Orbit TypeSun Orbit Type
Sunrise TimeUser-defined Sunrise Time
Sunset TimeUser-defined Sunset Time
Sun Dawn Offset TimeSets “Sun Dawn Time” depending on “Sunrise Time”.
Sun Dusk Offset TimeSets “Sun Dusk Time” depending on “Sunset Time”.
Sun Dawn TimeSun Dawn Time.
Sun Dusk TimeSun Dusk Time.
Sun ElevationSun Elevation angle in degrees.
Sun AzimuthSun Azimuth angle in degrees.
Sun Min Angle At Dawn & DuskMinimum angle of Sun below horizon at Dawn or Dusk.
Sun Fade In/Out TimeFade in/out time for Sun at Dawn or Dusk.

Moon Light

Moon Light MobilityMoon Light Mobility.
Control Moon DirectionWhether to control Moon direction by Sky Creator.
Use TemperatureWhether to use Color temperature for Moon.
Angular DiameterAngle subtended by light source in degrees (also known as angular diameter). Defaults to 0.5357 which is the angle for our sun.
Constant Atmosphere Disk Color ScaleWhether to use constant Atmosphere Disk Color Scale.
Atmosphere Disk Color ScaleA color multiplied with the sun disk luminance.
Moon PhaseMoon Disk Phase.
Moon RotationMoon Disk Rotation.
Moon Positioning
Moon Orbit TypeMoon Orbit Type.
Moonrise TimeUser-defined Moonrise Time.
Moonset TimeUser-defined Moonset Time.
Moon ElevationMoon Elevation angle in degrees.
Moon AzimuthMoon Azimuth angle in degrees.
Moon Fade In/Out TimeFade in/out time for Moon at Dawn or Dusk.

Exponential Height Fog

Exponential Height Fog MobilityExponential Height Fog Mobility.
Enable Exponential Height FogWhether to enable Exponential Height Fog.
Volumetric FogWhether to enable Volumetric fog. Scalability settings control the resolution of the fog simulation.
Fog Height OffsetFog height offset, relative to the actor position Z.
Second Fog Height OffsetSecond Fog height offset, relative to the actor position Z.

Star Map

Star Map TextureStar Map Texture
Rotation TypeStar Map Rotation Type
Additional RotationStar Map Additional Rotation

Occlusion

Occlusion CaptureWhether to enable realtime Occlusion Capture.
Occlusion Render TargetOcclusion Render Target.
Occlusion Capture WidthOcclusion Capture width. Half of this value is a radius.
Occlusion Capture HeightOcclusion Capture camera height.
Occlusion Capture Realtime UpdateOcclusion Capture realtime update. Expensive, so use with caution.
Occlusion Capture Step DistanceFixed distance step to update Occlusion Capture.
Occlusion BiasOcclusion Bias works similarly as known ‘Shadow Bias’ technique in shadow mapping. Low values can cause occlusion artifacts.
Occlusion Blur SamplesSample count of the Occlusion Blur.
Occlusion Blur DistanceBlurring distance of the Occlusion Blur.
Occlusion Mask Fade HardnessHardness of fading Occlusion radial mask.

Weather FX

Precipitation General
Precipitation Spawn RadiusPrecipitation spawn radius around the camera.
Enable Distant PrecipitationWhether to enable Distant Precipitation particles layer.
Increases overall amount of particles so can be turned off as an optimization step.
Distant Precipitation Spawn RadiusDistant Precipitation spawn radius around the camera.
Precipitation Max View DistanceMax distance at where precipitation particles will be alive.
Precipitation Vertical Check DistanceDistance of vertical linetrace from particle spawn point to check against occlusion.
Precipitation Collision ChannelCollision Channel for precipitation particles to check against.
Precipitation Depth Fade DistanceDepth Fade distance for precipitation particles.
Precipitation Camera Fade DistanceCamera Fade distance for precipitation particles.
Precipitation Camera Fade OffsetCamera Fade Offset distance for precipitation particles.
Rain
Rain Spawn Rate MaxMax number of rain particles to spawn per second.
Value is multiplied by “Rain Amount” value in weather preset.
Rain Distant Spawn Rate MaxMax number of distant rain particles to spawn per second.
Value is multiplied by “Rain Amount” value in weather preset.
Rain Distance Scale FactorScale Factor by distance for rain particles (for better visibility).
Rain Index Of RefractionIndex of Refraction for rain particles.
Set 1.0 for no refraction.
Rain Splash
Rain Splash Spawn Rate MaxMax number of rain splash particles to spawn per second.
Value is multiplied by “Rain Amount” value in weather preset.
Snow
Snow Spawn Rate MaxMax number of snow particles to spawn per second.
Value is multiplied by “Snow Amount” value in weather preset.
Snow Distant Spawn Rate MaxMax number of distant snow particles to spawn per second.
Value is multiplied by “Snow Amount” value in weather preset.
Snow Distance Scale FactorScale Factor by distance for snow particles (for better visibility).
Snow Mask HardnessMask Hardness for snow particles. Controls how ‘soft’ they look.

Weather Material FX

Wetness
Wetness Slope AngleSlope Angle for the Wetness effect.
Wetness Slope SmoothnessSlope Smoothness for the Wetness effect.
Puddles
Puddles Mask ScaleScale of the Puddles Mask in world units.
Puddles RoughnessRoughness of the Puddles effect.
Puddles Slope AngleSlope Angle for the Puddles effect.
Puddles Slope SmoothnessSlope Smoothness for the Puddles effect.
Ripples
Rain Ripples Update RateUpdate Rate of the Rain Ripples Solver. Higher values increases simulation speed.
Rain Ripples ScaleScale of the Rain Ripples in world units.
Rain Ripples Max DensityMax density of Rain Ripples when the amount equals “1”.
Wind Ripples ScaleScale of the Wind Ripples in world units.
Snow
Snow Mask ScaleScale of the Snow Mask in world units.
Snow ScaleScale of the Snow Material in world units.
Snow RoughnessRoughness of the Snow Material.
Snow Sparkles ScaleScale of the Snow Sparkles effect in world units.
Snow Sparkles RoughnessRoughness of the Snow Sparkles effect.
Snow Slope AngleSlope Angle for the Snow effect.
Snow Slope SmoothnessSlope Smoothness for the Snow effect.

Wind

Enable WindWhether to enable Wind. Affects Volumetric Clouds and Weather FX particles.
Independent Wind ControlIf set to true, Cloud & Weather FX Wind is controlled by either static values or by separate controller.
If set to false, Cloud & Weather FX Wind will read values from Weather Presets.
Editor Independent Wind SettingsEditor Independent Wind Settings.
Volumetric Cloud
Low Cloud Wind DirectionWind direction for Low Cloud Layer in angles
Low Cloud Wind SpeedWind speed for Low Cloud Layer in m/s
High Cloud Wind DirectionWind direction for High Cloud Layer in angles
High Cloud Wind SpeedWind speed for High Cloud Layer in m/s
Cloud Noise Wind DirectionWind direction for Cloud Noise in angles
Cloud Noise Wind Speed HorizontalHorizontal wind speed for Cloud Noise in m/s
Cloud Noise Wind Speed VerticalVertical wind speed for Cloud Noise in m/s
Cloud Wind Skew AmountSkew clouds towards Low Cloud Wind Direction. Affected by Low Cloud Wind Speed.
Weather FX
Precipitation Wind DirectionWind direction for Precipitation in angles
Precipitation Wind SpeedWind speed for Precipitation

Exposure

Use Built-in Exposure SettingsWhether to use built-in Exposure Settings.
Exposure MethodLuminance computation method.
Exposure Compensation CurveExposure compensation based on the scene EV100.
Used to calibrate the final exposure differently depending on the average scene luminance.
0: no adjustment, -1:2x darker, -2:4x darker, 1:2x brighter, 2:4x brighter, …
Exposure Metering MaskExposure metering mask. Bright spots on the mask will have high influence on auto-exposure metering and dark spots will have low influence.
Min BrightnessAuto-Exposure minimum adaptation. Eye Adaptation is disabled if Min = Max.
Auto-exposure is implemented by choosing an exposure value for which the average luminance generates a pixel brightness equal to the Constant Calibration value.
The Min/Max are expressed in pixel luminance (cd/m2).
Max BrightnessAuto-Exposure maximum adaptation. Eye Adaptation is disabled if Min = Max.
Auto-exposure is implemented by choosing an exposure value for which the average luminance generates a pixel brightness equal to the Constant Calibration value.
The Min/Max are expressed in pixel luminance (cd/m2).
Min EV100Auto-Exposure minimum adaptation. Eye Adaptation is disabled if Min = Max.
Auto-exposure is implemented by choosing an exposure value for which the average luminance generates a pixel brightness equal to the Constant Calibration value.
The Min/Max are expressed in EV100 when using ExtendDefaultLuminanceRange (see project settings).
Max EV100Auto-Exposure maximum adaptation. Eye Adaptation is disabled if Min = Max.
Auto-exposure is implemented by choosing an exposure value for which the average luminance generates a pixel brightness equal to the Constant Calibration value.
The Min/Max are expressed in EV100 when using ExtendDefaultLuminanceRange (see project settings).
Speed UpIn F-stops per second, should be >0.
Speed DownIn F-stops per second, should be >0.
Low PercentThe eye adaptation will adapt to a value extracted from the luminance histogram of the scene color.
The value is defined as having x percent below this brightness. Higher values give bright spots on the screen more priority but can lead to less stable results. Lower values give the medium and darker values more priority but might cause burn out of bright spots.
>0, <100, good values are in the range 70 .. 80
High PercentThe eye adaptation will adapt to a value extracted from the luminance histogram of the scene color.
The value is defined as having x percent below this brightness. Higher values give bright spots on the screen more priority but can lead to less stable results. Lower values give the medium and darker values more priority but might cause burn out of bright spots.
>0, <100, good values are in the range 80 .. 95
Histogram Log MinHistogram Min value. Expressed in Log2 (Luminance).
Histogram Log MaxHistogram Max value. Expressed in Log2 (Luminance).
Histogram Min EV100Histogram Min value. Expressed in EV100 when using ExtendDefaultLuminanceRange (see project settings).
Histogram Max EV100Histogram Max value. Expressed in EV100 when using ExtendDefaultLuminanceRange (see project settings).

Sky Creator Weather Settings

Here’s all settings list which is meant to be used by weather presets in runtime.

Sky Atmosphere

Rayleigh
Rayleigh Scattering ScaleRayleigh scattering coefficient scale.
Rayleigh ScatteringThe Rayleigh scattering coefficients resulting from molecules in the air at an altitude of 0 kilometer.
Rayleigh Exponential DistributionThe altitude in kilometer at which Rayleigh scattering effect is reduced to 40%.
Mie
Mie Scattering ScaleMie scattering coefficient scale.
Mie ScatteringThe Mie scattering coefficients resulting from particles in the air at an altitude of 0 kilometer.
As it becomes higher, light will be scattered more.
Mie Absorption ScaleMie absorption coefficient scale.
Mie AbsorptionThe Mie absorption coefficients resulting from particles in the air at an altitude of 0 kilometer.
As it becomes higher, light will be absorbed more.
Mie AnisotropyA value of 0 mean light is uniformly scattered.
A value closer to 1 means lights will scatter more forward, resulting in halos around light sources.
Mie Exponential DistributionThe altitude in kilometer at which Mie effects are reduced to 40%.
Absorption
Absorption ScaleAbsorption coefficients for another atmosphere layer.
Density increase from 0 to 1 between 10 to 25km and decreases from 1 to 0 between 25 to 40km.
The default values represents ozone molecules absorption in the Earth atmosphere.
AbsorptionAbsorption coefficients for another atmosphere layer.
Density increase from 0 to 1 between 10 to 25km and decreases from 1 to 0 between 25 to 40km.
The default values represents ozone molecules absorption in the Earth atmosphere.
Art Direction
Sky Luminance FactorScales the luminance of pixels representing the sky, i.e. not belonging to any surface.
Height Fog ContributionScale the sky and atmosphere lights contribution to the height fog when
SupportSkyAtmosphereAffectsHeightFog project setting is true.

Volumetric Cloud

Low Cloud Layer
Low Cloud CoverageCoverage level of Low Cloud layer.
Low Cloud DensityDensity level of Low Cloud layer.
Low Cloud AltitudeAltitude of Low Cloud layer.
Low Cloud HeightHeight of Low Cloud layer.
Low Cloud Height VariationHeight Variation of Low Cloud layer.
Low Cloud Secondary CoverageCoverage level of Low Cloud Secondary layer.
Low Cloud Secondary AltitudeAltitude of Low Cloud Secondary layer.
Low Cloud Secondary HeightHeight of Low Cloud Secondary layer.
High Cloud Layer
High Cloud CoverageCoverage level of High Cloud layer.
High Cloud DensityDensity level of High Cloud layer.
High Cloud HeightHeight of High Cloud layer.
High Cloud Amount Type AAmount of ‘Type A’ clouds in High Cloud layer.
High Cloud Amount Type BAmount of ‘Type B’ clouds in High Cloud layer.
High Cloud Amount Type CAmount of ‘Type C’ clouds in High Cloud layer.
Cloud Lighting
AlbedoAlbedo color of Volumetric Clouds.
Albedo BottomAlbedo color of the bottom of Low Cloud layer.
Bottom DarkeningDarkening amount of the bottom of Low Cloud layer.
Night EmissiveEmissive color of Volumetric Clouds. Better to keep this value low.
Phase GPhase function describing how much forward (G < 0) of backward (G > 0) light scatter around.
Phase G2Second phase function describing how much forward (G < 0) of backward (G > 0) light scatter around.
Phase BlendLerp factor when blending the two phase functions.
Multi Scattering ContributionMulti-scattering approximation: represents how much contribution each successive octave will add. Evaluatead per pixel.
Multi Scattering OcclusionMulti-scattering approximation: represents how much occlussion will be reduced for each successive octave. Evaluatead per pixel.
Multi Scattering EccentricityMulti-scattering approximation: represents how much the phase will become isotropic for each successive octave. Evaluatead per pixel.
Cloud Noise
Shape Noise ErosionErosion amount of ‘Shape’ 3D Noise.
Detail Noise ErosionErosion amount of ‘Detail’ 3D Noise.

Sky Light

IntensityTotal energy that the light emits.
Light ColorFilter color of the light.
Note that this can change the light’s effective intensity.
Lower Hemisphere ColorLower Hemisphere Color.

Sun Light

IntensityMaximum illumination from the light in lux.
Light ColorFilter color of the light.
Note that this can change the light’s effective intensity.
TemperatureColor temperature in Kelvin of the blackbody illuminant.
White (D65) is 6500K.
Volumetric Scattering IntensityIntensity of the volumetric scattering from sun.
This scales Intensity and Light Color.
Atmosphere And Cloud
Atmosphere Disk Color ScaleA color multiplied with the sun disk luminance.
Cloud Scattered Luminance ScaleScales the lights contribution when scattered in cloud participating media.
Cloud Shadow StrengthThe overall strength of the cloud shadow, higher value will block more light.
Cloud Shadow on Atmosphere StrengthThe strength of the shadow on atmosphere. Disabled when 0.
Cloud Shadow on Surface StrengthThe strength of the shadow on opaque and transparent meshes. Disabled when 0.

Moon Light

IntensityMaximum illumination from the light in lux.
Light ColorFilter color of the light.
Note that this can change the light’s effective intensity.
TemperatureColor temperature in Kelvin of the blackbody illuminant.
White (D65) is 6500K.
Volumetric Scattering IntensityIntensity of the volumetric scattering from moon.
This scales Intensity and Light Color.
Atmosphere And Cloud
Atmosphere Disk Color ScaleA color multiplied with the moon disk luminance.
Cloud Scattered Luminance ScaleScales the lights contribution when scattered in cloud participating media.
Cloud Shadow StrengthThe overall strength of the cloud shadow, higher value will block more light.
Cloud Shadow on Atmosphere StrengthThe strength of the shadow on atmosphere. Disabled when 0.
Cloud Shadow on Surface StrengthThe strength of the shadow on opaque and transparent meshes. Disabled when 0.

Exponential Height Fog

Fog
Fog DensityGlobal density factor of fog.
Fog Height FalloffHeight density factor, controls how the density increases as height decreases.
Smaller values make the visible transition larger.
Fog Inscattering ColorFog Inscattering Color.
Fog Start DistanceDistance from the camera that the fog will start.
Second Fog
Second Fog DensityGlobal density factor of secondary fog.
Second Fog Height FalloffHeight density factor, controls how the density increases as height decreases.
Smaller values make the visible transition larger.
Directional Inscattering
Directional Inscattering ExponentControls the size of the directional inscattering cone, which is used to approximate inscattering from a directional light.
Note: there must be a directional light with bUsedAsAtmosphereSunLight enabled for DirectionalInscattering to be used.
Directional Inscattering Start DistanceControls the start distance from the viewer of the directional inscattering, which is used to approximate inscattering from a directional light.
Note: there must be a directional light with bUsedAsAtmosphereSunLight enabled for DirectionalInscattering to be used.
Directional Inscattering ColorControls the color of the directional inscattering, which is used to approximate inscattering from a directional light.
Note: there must be a directional light with bUsedAsAtmosphereSunLight enabled for DirectionalInscattering to be used.
Volumetric Fog
Volumetric Fog Scattering DistributionControls the scattering phase function – how much incoming light scatters in various directions.
A distribution value of 0 scatters equally in all directions, while .9 scatters predominantly in the light direction.
In order to have visible volumetric fog light shafts from the side, the distribution will need to be closer to 0.
Volumetric Fog AlbedoThe height fog particle reflectiveness used by volumetric fog.
Water particles in air have an albedo near white, while dust has slightly darker value.
Volumetric Fog EmissiveLight emitted by height fog. This is a density so more light is emitted the further you are looking through the fog.
In most cases skylight is a better choice, however right now volumetric fog does not support precomputed lighting, so stationary skylights are unshadowed and static skylights don’t affect volumetric fog at all.
Volumetric Fog Extinction ScaleScales the height fog particle extinction amount used by volumetric fog.
Values larger than 1 cause fog particles everywhere absorb more light.

Star Map

Star Map BrightnessOverall brightness of the Star Map.
Star Map Color TintOverall color tint of the Star Map.
Star Map Twinkle IntensityIntensity of twinkling stars.
Star Map Twinkle SaturationSaturation of twinkling stars.
Star Map Twinkle SpeedTwinkle speed of stars.
Star Map Horizon ThresholdIndicates how strong the star map can be faded into horizon.
Lower values cause more stars appear at horizon.
Star Map Atmosphere ThresholdIndicates how strong the star map can be faded into atmosphere.
Lower values cause more stars appear at brighter points in atmosphere, e.g. at daytime.
Night Horizon ColorColor tint of the horizon.
Night Zenith ColorColor tint of the zenith.

Weather FX

Rain
Rain AmountRain Amount.
Rain ColorRain Color.
Rain Gravity MinMinimum gravity of a single raindrop.
Rain Gravity MaxMaximum gravity of a single raindrop.
Rain Lifetime MinMinimum lifetime of a single raindrop. Can affect the performance.
Rain Lifetime MaxMaximum lifetime of a single raindrop. Can affect the performance.
Rain Size MinMinimum size of a single raindrop.
Rain Size MaxMaximum size of a single raindrop.
Rain Length MinMinimum length of a single raindrop.
Rain Length MaxMaximum length of a single raindrop.
Rain Splash
Rain Splash Size MinMinimum size of a rain splash.
Rain Splash Size MaxMaximum size of a rain splash.
Snow
Snow AmountSnow Amount.
Snow ColorSnow Color.
Snow Gravity MinMinimum gravity of a single snowflake.
Snow Gravity MaxMaximum gravity of a single snowflake.
Snow TurbulenceSnow turbulence.
Snow Lifetime MinMinimum lifetime of a single snowflake. Can affect the performance.
Snow Lifetime MaxMaximum lifetime of a single snowflake. Can affect the performance.
Snow Size MinMinimum size of a single snowflake.
Snow Size MaxMaximum size of a single snowflake.

Weather Material FX

Wetness
Wetness AmountWetness Amount.
Wetness ColorWetness Color.
Puddles
Puddles AmountPuddles Amount.
Puddles ColorPuddles Color.
Ripples
Rain Ripples AmountRain Ripples Amount.
Rain Ripples IntensityRain Ripples normap map intensity.
Rain Ripples Force Min RadiusMin Force Radius to write by the Rain Ripples Solver.
Rain Ripples Force Max RadiusMax Force Radius to write by the Rain Ripples Solver.
Rain Ripples Rings NumberNumber of Rain Ripples Rings to propagate by a single raindrop.
Rain Ripples Rings DelayDelay of Rain Ripples Rings propagation. Number represents Rain Ripples Solver frames to skip.
Rain Ripples DampingDamping of Rain Ripples. Higher values are fading Rain Ripples faster.
Wind Ripples IntensityWind Ripples normap map intensity.
Wind Ripples SpeedSpeed of the Wind Ripples.
Snow
Snow AmountSnow Coverage Amount.
Snow ColorSnow Coverage Color.
Snow IntensitySnow normap map intensity.
Snow Sparkles ThresholdSnow Sparkles Threshold. Lower values exposes more sparkles.

Wind

Volumetric Cloud
Low Cloud Wind DirectionWind direction angle of Low Cloud layer in degrees.
Low Cloud Wind SpeedWind speed of Low Cloud layer in m/s.
High Cloud Wind DirectionWind direction angle of High Cloud layer in degrees.
High Cloud Wind SpeedWind speed of High Cloud layer in m/s.
Cloud Noise Wind DirectionWind direction angle of Cloud Noise in degrees.
Cloud Noise Wind Speed HorizontalHorizontal wind speed of Cloud Noise in m/s.
Cloud Noise Wind Speed VerticalVertical wind speed of Cloud Noise in m/s.
Weather FX
Precipitation Wind DirectionWind direction angle of precipitation particles in degrees.
Precipitation Wind SpeedWind speed of precipitation particles.

Exposure

Exposure CompensationLogarithmic adjustment for the exposure. Only used if a tonemapper is specified.
0: no adjustment, -1:2x darker, -2:4x darker, 1:2x brighter, 2:4x brighter, …

To be updated.

Changelog

V1.00

  • Initial release

V1.01

  • Deleted two legacy unused functions which were triggering an error “Explicit Category is required …” when packaging a build
  • Moved Rain & Snow particle emitters from GPU to CPU, which fixes an error “Assertion failed: OnRequestDefaultDataInterface.IsBound() …”. This is probably an engine bug, deserves a further investigation. This can be just a temporary solution for now
  • Default values to Rain & Snow particle count are reduced because CPU emitters are usually more expensive
  • Fixed wrong material link in static mesh “SM_SC_SkySphere”
  • Moved “Volumetric Cloud MID” variable in “Debug” Category
  • Reverted to false default “Per Pixel Atmosphere Transmittance” boolean values to Sun and Moon (can cause “shadow zones” if surface is below Planet Top of Sky Atmosphere)

V1.02

  • Fixed Moon disk direction when Sky Creator actor is rotated
  • Fixed visual bug with long Cloud Wind Skew when editing clouds in editor
  • Fixed Second Fog control in Exponential Height Fog
  • Lowered default value for Cloud Shadow Extent from 50 to 25 in Sun & Moon (better cloud shadows with same performance)

V1.03

  • Changed Volumetric Cloud material shading model to “Default Lit” instead of “Unlit” (makes no difference in UE4 4.26, but it does in UE5)
  • Added engine major version verification when initializing FPlaceableItem in editor module (that struct is a bit different between UE4 and UE5)

V1.04

  • Fixed Moon Disk sorting priority in sky material – stars are properly occluded now
  • Fixed Moon Mask aliasing
  • Fixed “Auto Scale” for Volumetric Cloud Noise
  • Fixed “Cloud Wind Skew”
  • Added “SkyCreator_CinematicController” blueprint specifically for Sequencer
  • Added Moon Disk Rotation
  • Added ability to choose between “Editor Weather Preset” and “Editor Weather Settings” – second option is for direct variable control
  • Added two new quality options for Volumetric Cloud – “Ground Contribution” and “Multi Scattering Approximation Octave Count”
  • Renamed “Sample Count Scale” subcategory to “Quality” in Volumetric Cloud options
  • Renamed “Sync With Low Cloud Map Scale” variable to “Auto Scale” in Volumetric Cloud options

V1.05

  • Fixed “Explicit Category is required …” in a Volumetric Cloud Materials struct when packaging a build

V1.10

  • Enhanced Rain & Snow including many improvements
  • New Rain Splashes effect
  • Expanded Exposure settings supporting “Extended Luminance Range”
  • Lower Hemisphere Color for Sky Light (useful for night lighting)
  • Sun Light Intensity in Weather Settings is now “40.0”
  • Moon Light Intensity in Weather Settings is now “0.02”
  • Min Brightness for Exposure is now “0.02”
  • Speed Up and Speed Down for Exposure are now “4.0”
  • Fixed a typo in “Bottom Altitude” variable

V1.11

  • New Cloud settings for Sun Light & Moon Light
  • New Star Map Threshold settings
  • New Star Map Twinkle settings
  • Added “Use Editor Time of Day” & “Use Editor Weather Settings”
  • Commented all visible variables
  • Unclamped variables where it was unnecessary
  • Added missing line “Super::GetLifetimeReplicatedProps(OutLifetimeProps)” to the replication function

V1.12

  • Displaying debug variables now can be turned off by a checkbox “Show Debug Variables”
  • Changed default “Fog Inscattering Color” from black to dark blue color (improves lighting at nights)
  • Modified ConstructorStatics calls in SkyCreatorActor.cpp
  • Added missing “Lower Hemisphere Color” parameter in the “Lerp Sky Light Settings” function
  • Fixed empty reference in “MI_SC_SkySphere”
  • Fixed empty reference in “MI_Demo_01”
  • Fixed “ObjectProperty is not initialized properly” warnings
  • Fixed casting static shadows from Compass mesh

V1.20

  • Added dynamic Occlusion Capture
  • Added new Weather Material FX – Wetness
  • Added new Weather Material FX – Puddles
  • Added new Weather Material FX – Ripples (including built-in Ripples Solver)
  • Added new Weather Material FX – Snow
  • Added new blueprint “SkyCreator_CaptureDistantOcclusion”
  • Added new blueprint “SkyCreator_DebugOcclusion”
  • Debug category is now deprecated – now all debug variables are placed at corresponding categories. They are still not visible by default, but can be turned on by “Show Debug Variables” checkbox
  • Updated “SkyCreator_ControllerExample” – now it has Accumulation/Dry timers for the new Weather Material FX
  • Updated Demo map
  • Updated default Weather Settings to be slightly more pleasing to the eye
  • Updated all Weather Presets and added a few more
  • Updated Rain material to be slightly more soft looking

V1.21

  • Added Real Sun & Moon Positioning
  • Moved all Sun & Moon position settings into new single category “Sun & Moon Position”
  • Reworked “Light Transition” hardcoded feature. Transitions between Sun & Moon are noticeably smoother now
  • Direction of the North has changed from Y- to X+ to match Unreal’s yaw angle rotation
  • Disabled Cloud Shadows of MoonLight component by default
  • Fixed wrong color conversion with Volumetric Fog Albedo in Weather Settings
  • Minor changes to code to have UE 5.0 Preview compatibility

V1.22

  • Added Camera Velocity Alignment effect for Rain FX
  • Added Moon Phase Light Intensity Scale
  • Moon Disk color (or “Atmosphere Disk Color Scale”) is now independent of Moon Intensity and Moon Light Color
  • Precipitation FX is now rendered before DOF
  • Increased default Rain Splash amount x2
  • Fixed crash when trying to change Sun or Moon Position Type variable of a blueprint child of Sky Creator
  • Fixed Rain Splash fading

V1.23

  • Added GPU Precipitation Particles feature
  • Added Motion-based Alignment & Elongation for Precipitation particles
  • Added Unified Gravity settings for Precipitation particles
  • Added Constant Sun & Moon Intensity
  • Redesigned Rain, Rain Splash and Snow materials (better blending with a scene and better visibility)
  • Deleted “Distant Precipitation” feature (replaced by GPU Precipitation)
  • Deleted “Index of Refraction” settings
  • Deleted “Rain Length Min” and “Rain Length Max” variables are obsolete now
  • Replaced “Gravity Min” and “Gravity Max” with a single “Gravity” variable
  • Renamed “Camera Velocity Alignment” to “Camera Motion Alignment”
  • Changed “Snow Spawn Rate Max” default value to 1000
  • Changed some minor default weather preset settings
  • Declared some functions as virtual
  • Fixed Occlusion Capture not happening at the level load
  • Fixed “Niagara Shader Module Delegate Never Set” crash in packaged builds