Documentation

Sky Creator for Unreal Engine 4
Available on Marketplace
Current version: 1.12

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 UE4 4.26.
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 and then it will recompile plugin’s binaries from source. Also be sure to have Visual Studio and Windows 10 SDK installed on your machine to be able to compile source code.

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.

Sky Creator Actor Settings

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

General

Editor Time of DayEditor Time of Day
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 Sphere RadiusSky Sphere mesh radius in kilometers

Sky Atmosphere

Sky Atmosphere MobilitySky Atmosphere Mobility
Transform ModeTransform Mode
Planet RadiusThe planet radius (kilometers from the center to the ground level).
Atmosphere HeightAtmosphere Height from ground in kilometers
Trace Sample Count ScaleScale the atmosphere tracing sample count. Quality level scalability

Volumetric Clouds

Bottom AttitudeThe 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 (kilometers)
Tracing Max DistanceThe maximum distance that will be traced inside the cloud layer (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 (length and width)
Low Cloud Map OffsetLow Cloud Map tileable texture UV offset
High Cloud Map
High Cloud Map ScaleHigh Cloud Map tileable texture scale in kilometers (length and width)
High Cloud Map OffsetHigh Cloud Map tileable texture UV offset
High Cloud Horizon Fade HardnessHigh Cloud Horizon Fade Hardness
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.

Sun Light

Sun Light MobilitySun Light Mobility
Control Sun DirectionWhether to control Sun direction by Sky Creator
Use TemperatureColor temperature in Kelvin of the blackbody illuminant. White (D65) is 6500K.
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.
Sun Positioning
Sun Orbit TypeSun Orbit Type
Sunrise TimeArbitrary Sunrise Time
Sunset TimeArbitrary Sunset Time
Sun Dawn Offset TimeSets Sun Dawn Time by an offset from Sunrise Time.
Sun Dusk Offset TimeSets Sun Dusk Time by an offset from 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 TimeSun Fade In/Out Time after Dawn or before Dusk

Moon Light

Moon Light MobilityMoon Light Mobility
Control Moon DirectionWhether to control Moon direction by Sky Creator
Use TemperatureColor temperature in Kelvin of the blackbody illuminant. White (D65) is 6500K.
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 TimeArbitrary Moonrise Time
Moonset TimeArbitrary Moonset Time
Moon ElevationMoon Elevation angle in degrees
Moon AzimuthMoon Azimuth angle in degrees
Moon Fade In/Out TimeMoon Fade In/Out Time after Dawn or before 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

Weather FX

Precipitation Spawn RadiusPrecipitation spawn radius from camera
Max Rain ParticlesMaximum rain particles at Rain Amount = 1
Max Snow ParticlesMaximum snow particles at Snow Amount = 1

Wind

Enable WindWhether to enable Wind
Independent Wind ControlWhether to use wind control settings that are independent 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 AmountCloud wind skew amount that is 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 SettingsExposure Settings

Sky Creator Weather Settings

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

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