How would one add multiple cameras on top of each other? I’m trying to emulate the layered camera effect in Unity3D, where one camera would render on top of another, with the ability to define viewport coverage?
There are some answers for the question, the content of which is that you have to convert C++ code, but it is too difficult for me. If only there are some easier solution…
This question was posted in 2014. 
There are now multiple ways to do, the easiest being USceneCaptureComponents.