koobas.hobune.stream
How to display two scenes in one screen?
I have 2 scenes and want to split screen in 2 parts. Each part displays own scene and handles mouse clicks. 
I try to use "add scene additive", but it just adds own object tree to active scene. I need separate scenes in each part and be able to determine mouse events in both scenes.
Is the way to implement that in Unity?
I Found out the error
In the layer manager add new layers 2d and 3d
In the Camera Settings of 2d camera
Find culling mask
In the culling settings
Remove 3d
Do the reverse in the 3d camera
Now in the objects you want to set 2d add 2d layer and the opposite in 3d
Use Open scene additive
In the inspector of the camera (3d scene)
Go to Camera > Viewport Rect
use these settings 
In the inspector of the camera (2d scene)
Go to Camera > Viewport Rect
use these settings 
As I mentioned, in such way both cameras display all objects of two scenes. 
I need to see only 3d objects in first camera and 2d objects in second camera.
It must be some error in your installation I see Objects according to scene
