Over the past few days I have been searching around trying to develop a way to recreate the effect of UTPortals from UDK/UE3 in Unreal Engine 4. SceneCapture cameras that move relative to the player combined with render targets can be used to create a crude version of the effect, but are laggy and far from an optimal solution. Unfortunately, it does not seem possible to recreate the effect in a convincing/practical way without delay or resolution issues.
These actors allowed for a 3d projection of a different area of a level to be displayed on a plane. Projectiles, players and other objects were teleported between the portal planes. UTPortals were an extremely interesting feature which provided a wide range of options for level designers and artists alike, including impossible geometry and non-euclidean level architecture. For me personally, they are essential to the concept behind one of my projects and I was hoping that an improved version would be included in UE4, but to no avail. I have even considered returning to UDK just so I can access this feature. I have seen several other individuals attempt to recreate UTPortals in blueprint, but the result fails to hold up to the original.
For these reasons, I ask Epic to consider re-implementing a UTPortal-type feature into UE4. I’m sure that with the power of UE4, the UTPortal actor could be vastly improved upon, and would be a well-received future (re)addition to the engine.