Just getting a "floor plan" or empty room is much easier. But yes, it's an active area of research in Computer Vision / Graphics. Later on in the article it sa

Just getting a "floor plan" or empty room is much easier. But yes, it's an active area of research in Computer Vision / Graphics. Later on in the article it says "90% automated" and that things are checked. That'll be good enough to make this cost feasible. Disclaimer: I'm related to one of the founders (but I don't work there).