portal

A doorway, window or opening between two rooms (or a room and the outdoors) for room visibility: a rectangle centred on the object, facing its +Z. The rooms it joins are found from where it stands. state open: seen through; closed: a shut door, nothing beyond is drawn through it; boarded: planks with gaps, still seen through. Scripts open and close it with the door.

In scene text

portal { size (0, 1, 0)  state "…" }

Add it in the Inspector (Add Component), in scene text as above, or ask your AI. Fields you leave out keep their defaults.

Fields 2