Working with trueSKY from GitHub

1: Access to Repository

  1. Make sure you have created a Simul account. If not, head over here to register.

  2. On your Account Page, there is a GitHub Username section. Input your GitHub Username and select Request Access. This needs to be the same username connected to your Unreal Engine account at

  3. You will receive an email from with an invitation to join the Simul UnrealEngine group. Click the link in the email and accept the invitation.

  4. You should now have access to our Unreal Repo at

  5. Fork or clone our Unreal Repository. If you are not sure how to do this, GitHub has helpful information here. Alternatively, if you are using a different UE4 codebase, pull changes from the Simul fork, and merge.

2: Setup

  1. Follow the UE4 ReadME (in the root UnrealEngine directory), making sure you:
    • Run Setup.bat to download all complementary UE4 dependencies.

    • Run GenerateProjectFiles.bat from the UE4 root directory; this will generate projects and the solution file (UE4.sln).

  2. The trueSKY binary libraries are not kept in the repository. This is because multiple trueSKY versions can work with the same Unreal version. So, to get the binary libraries, you can either:
    • Run the batch file located in Engine/Plugins/TrueSkyPlugin/GetBinaries.bat, passing in the required trueSKY version as a parameter, for example as: GetBinaries.bat 4.2.

    • Or, go to our downloads page and get the appropriate TrueSkyUE4Binaries installer. Make sure to choose the correct Unreal Engine install directory.

  3. In both cases this will auto-extract (upon your permission) trueSKY binaries (DLLs/LIBs) into [UE4]/Engine/Binaries/ThirdParty/Simul. Binaries are then put into their platform-respective paths, while the trueSKY shader files will go into your TrueSkyPlugin directory under the shaderbin subfolder (these are also separated based on platform).

  4. Use UE4.sln to open the project in Visual Studio.The UE4 project contains the “TrueSkyPlugin” folder in Engine/UE4/Plugins (whether you installed via the installer or downloaded the source from GitHub). There are two trueSKY modules in the UE4 project – TrueSkyPlugin and TrueSkyEditorPlugin. TrueSkyEditorPlugin is only built alongside an editor build of UE4.

  5. Build the UE4 project in the “Development Editor” configuration. Once this has compiled trueSKY will be present in your UE4 build.

Full Integration with Custom Unreal Source Code

The following files in the UE source have been modified in the Simul fork of the UE4 repository. If you are merging trueSKY into a custom fork, you must ensure that the trueSKY modifications are carried over. In general, a good way to go about merging these changes is by using Beyond Compare or Perforce Merge to easily do a diff across repos or, even simpler, between separate folders on your local machine.

Core Engine Files:

  • Engine/Source/Runtime/Renderer/Private/DeferredShadingRenderer.cpp

  • Engine/Source/Runtime/Renderer/Public/RendererInterface.h or Engine/Source/Runtime/RenderCore/Public/RendererInterface.h

  • Engine/Source/Runtime/Renderer/Private/RendererModule.h

  • Engine/Source/Runtime/Renderer/Private/SceneRendering.cpp

  • Engine/Source/Runtime/Renderer/Private/RendererScene.cpp

  • Engine/Source/Runtime/Renderer/Private/TranslucentRendering.cpp

Deployment File (Windows):

  • Engine/Source/Programs/AutomationTool/Win/WinPlatform.Automation.cs

Deployment Files (XBox One):

  • Engine/Source/Programs/UnrealBuildTool/XboxOne/XboxOneDeploy.cs

  • Engine/Source/Programs/AutomationTool/XboxOne/XboxOnePlatform.Automation.cs

Deployment Files (Playstation 4):

  • Engine/Source/Programs/AutomationTool/PS4/PS4Platform.Automation.cs

  • Engine/Source/Programs/UnrealBuildTool/PS4/UEDeployPS4.cs