Building 3d models is a total time consuming pain in the ass.
Virtual virtual would be enough , ie a panoramic picture or better - a 3d camera film.
Then the builder can look at it in a browser on his iphone - which is all you can expect from a builder.
you CANNOT expect him to jump on 3DMAX and build you a dxf of what you will get.
Even if you provided him with the "exisiting setup"
I guess the most likely of the fantasy instant=3d-model scenario the author mentions is that if you have a good walk round with a 3d camera , some software could analyse the different angles and make it 3d - which is how i poresume google satallite view does tha 3d trick - whicj i think is pretty impressive. Bet it takes a few datacentres to do it tho
It would be nice if houses came with proper 3d models from the manufacturers , or even a fucking decent description of where the boundaries are , never mind the wiring. All I got for thousands of pounds worth of "Conveyancing" was a top down diagram of the whole estate , my house being half the size of a postage stamp.