It\'s the problem with edition tools : people tend to become lazy. Tassyr I\'m not saying you are lazy, but my point is : if you want to build an asteroid-looking-giant-ship, at some point you are going to work on it by hand. It might not be the most interesting task, but you\'ll have to do it.
Or, instead of filling it, you could build everything inside, hangars, rooms, shields, power, weapons, and THEN, fill the unused space. In my opinion it will be easier to work in an empty space.