I am trying to hide custom objects/part of objects through a invisible wall as shown in image below
Any ideas?
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You have to do something crafty in the cube material, not exactly sure what. But I do know that this package already does it for you:
And, no, it’s not my package… 
Hey there!
I was looking for the same thing before and I found my own answer
Probably it’s possible using materials magic but I am not a specialist there
Personally I used the Scene Capture Component 2D - it has a built in array called “Hidden Actors”
If you separate cubes to be separate actors you can control that
If you’re interested in the post with my solution - head Over here - I used rthis technique to make a shield that will hide a player behind it in the way you show on the screenshots
It’s gonna be hard to implement exact background tbh - you’ll need a plane and probably a piece of code controlling the camera rotation to fit the background view as it’s gonna be distorted as you move away or to the sides
Maybe that’s gonna be your answer, if not - you’ll need a material specialist 
Wish you luck!
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