How could I turn the screen into a mesh and split it up?

Hello, I want to make some transition effects for entering an area. I have a basic high level idea of how I would do this :

Render the current screen into a mesh .
Begin loading level behind it.

Manipulate mesh for an effect.

One of the transitions I’m interested in doing is like a breaking screen effect. I figure I would need to break the mesh into pieces then applie physics or movement to them.

The problem is I have no idea how to actually do any if the steps above in ue4. How do I create a mesh from my cymurrent screen? And how can I break up a mesh?

If anyone can give any guidance it would help! Thanks.