I don't see why not Just like anything else, don't make it floating over someone else's existing base and you'll probably be okay
I had him ask to make sure, I might have not remembered correctly but i thought they were not allowed. I remember that someone called them "unethical" or was it "not clean" either way just having him make sure.
haha. Well, if you make a floating island the size of the explored map and blot out the sun for everyone, I may have something to say about it. If you make a floating island the size of a small number of chunks, and don't infringe on anyone else's space, it'll be fine. Bonus points if you build something to make it look like the island is anchored to the ground (one of my plans at some point )
