Getting Started
Viewport worlds are experimental and we do not provide any support for it. This is because Unreal Engine itself does not support the concept of having secondary world running inside game world.
Before we begin, let's understand what exactly is viewport world. Viewport World lets you create a new UWorld inside Operating System World allowing you to play a game inside Operating System itself. To get an idea, here are some previews of Viewport World.
Playing a game preview​
This video shows a game world with widgets playing inside Operating System World.
Virtualization simulation preview​
This preview shows virtualization simulation similar to softwares like VirtualBox, VMware etc.
Secondary world communication preview​
Communicate with the game world using our Global Messenger Subsystem.
Viewport worlds are disabled by default because of their experimental nature and must be explicitly enabled by the developer, who must acknowledge that it is an experimental feature and might not support all types of levels. Go to Project Settings -> Viewport World -> Settings and select Enable Viewport Worlds (Experimental).
You can now open any UMG widget Blueprint and drag 'n' drop a viewport world widget which will host your target world.