Apis Cor seems to have a more complete prototype:<p><a href="https://www.youtube.com/watch?v=xktwDfasPGQ" rel="nofollow">https://www.youtube.com/watch?v=xktwDfasPGQ</a>
Could you use a combination of powerline supplied drones to give the "printing head" greater independence?<p>Basically a Zeppelin setup, carrying the basic load, with a drone on a pipe controlling the precise placement?