"The big advantage of this system is that you can use it to build…

"The big advantage of this system is that you can use it to build structures that are more or less arbitrary in size without having to change the system all that much, since the robots themselves can define their own build volume by moving around. These are robot arms on mobile bases, of course, not drones, so there are still restrictions on how high they can reach, but they still have way more flexibility than other systems when it comes to length and width. They can also potentially be much more efficient, since you can throw a bunch of robots at a big project, with each one tackling a different piece at the same time. Besides improving the overall speed of the print, having multiple robots also means that you can make stronger, more complex structures, since you don’t run into the problem of trying to bond wet concrete to dry concrete where two parts intersect."

https://spectrum.ieee.org/automaton/robotics/industrial-robots/mobile-robots-cooperate-to-3d-print-structures