Looks absolutely gorgeous!
Very interesting post, thanks for sharing! Next step would be to procedurally create the indoors! I understand your point about a semi-procedural approach. I often fall into the go-full-procedural vortex and can't get things done. :D Anyway, one question I don't quite get why "fill the interior" on the vdb node has to be checked?
it is really frustrating that half the article was posted and i cannot view the end of this article, every possible link on the page refers to the same url and that url is password protected. creation of a gametextures account will not get you access to the end of this page so don't hand them paypal info like I did just go blunder off through a youtube tutorial rather than this good-old-boy referral page