How do I make Portal 2 portal rendering and use, or how to create a portal at least quite similar to portal 2's mechanics

Hi, and thanks for coming to my post.
Im a massive fan of the portal games, portal, portal 2, and the mods of portal, of course.
I’ve watched numerous tutorials, but haven’t been able to create a portal effect. The only videos that recreate this almost PERFECTLY, are from the days of Unreal Engine 3. If someone knows how to reproduce this effect in unreal engine 4, I would love to hear from you. But, also, if you don’t have an answer and you are a unreal engine developer, maybe you could fix these problems in this video-(Its not by me) That thing about portals... - YouTube . A lot of people have asked for help in this current subject, and there is no way to reproduce the effect perfectly for the current time. I would love, absolutely LOVE, to be a dev of a portal game in unreal engine. The ones that make me feel that they are most like portal are the ones from UE3. like these two. UDK - More portals in UE3! - YouTube , and this one from vimeo - Portal Gun for Unreal Engine 3 on Vimeo .
I hope that there will be a update, or something that can fix this problem with portals. Thank you for reading the entirety of my post, and I hope that you, if you are looking for an answer as well, will find it.

~GAMECR3ATRZ