This is a little late to my own party - I made this environment over a year ago and wrote this 80 Level article that was published in October 2018. I wrote about it in my ArtStation blog at the time, tweeted about it, etc. But it turns out, not many people know that when looking in my portfolio, so it's about time I upload this to my portfolio for real.
Please, keep in mind that this isn't the ultimate work-flow or exactly how I work today (a lot has changed in 1 year), it's just some odd methods I tried at the time.
Link to article on 80 Level here: https://80.lv/articles/001agt-004adk-creating-a-dungeon-with-maya-substance-designer/
Original project: https://www.artstation.com/artwork/kgyvy