Comment by Mountain_Skies

A friend invented a device to do that. It was a small backpack you (or whoever is making the listing) would wear and walk into each room of the building. After gathering the data, software would turn it into a floorplan. It probably took less time per room than getting good listing photos. Not sure why she never went to market with it but I'm going to guess something similar could be done now with just a modern smartphone and the right software.