Parallax occlusion portal effect I'd like to create a parallax occlusion effect (cycles or eevee) where a cube or plane appears to contain another universe inside of it. I've seen a lot of brilliant solutions that can fake it using 2D images, but I'm wondering if there is a solution that would allow for objects within the plane to actual "pop out", like below --



These solutions all work well for 2D planes, and I know a lot of people use this to create fake rooms inside buildings, but again you're stuck using flat images that can't cross the border of the plane. I also think anything to with compositing nodes would make the effect I'm going for impossible.


https://twitter.com/Magryllia/status/1129566134024396800
Portal effect in EEVEE?
How to make a holographic reticle shader in cycles)
One way si to build both worlds inside one scene.
And then fake an 'infinitely deep' wall between them.




Build one set (I used an HDRI) 
Add a wall with a 'portal' cutout.
Add a texture to this wall (I used stars) and use Texture Coordinate node > Window to map it.
The texture will always be facing towards you, faking an infinitely deep space.


Since both worlds are actually inside one scene, you can freely move objects between them.

I'm not rotating the portal, I'm moving the camera.