This video is my first attempt at this system. At this point the portal links hadn't yet been developed, and I was just developing the material/cameras for the plane.
Here I had started developing the portal system. When the character hits the plane they are teleported inside the big dome (TARDIS interior) that is visible behind the TARDIS exterior in this video.
This is my most up-to-date test of this. My current hurdles, as seen in the video, are the doors clipping through the plane, a slight jump forward after teleporting, and lighting not displaying correctly on the image plane compared to when in the TARDIS.
This post is to show the various stages of the portal system I have been developing using blueprint nodes. In these videos, I have used a method where you place two planes down in different places. As the player hits one plane, they are then teleported to the connected plane. The image of the inside/outside of the TARDIS was achieved by using a camera and linking what that camera captures to a material, which is then applied to the opposite plane. The cameras are then linked to the player character so that when the player moves, the capture camera moves in relation to the character, giving the illusion the TARDIS is bigger on the inside.