Fixed screen background

How to create a “skybox” that shows the same image or the same texture wherever you look at it? Like a layer below all gui, below all 3d objects.

You will want to create a custom camera actor and then in the blueprint you can create a sprite component that is offset from the camera component by a set distance, into Y, or whatever. This sprite will always appear behind the camera by whatever distance you set in the blueprint viewport.

As you are using a custom camera actor, you will need to set it as the view target, which is detailed here.

I expected there was a much elegant or a single-click solution. Well, whatever works.

Also you can use a plane instead of a sprite component, don’t have to include Paper 2d plugin.