[quote=@Willy Vereb] I can't see any difficulty for an industry that can break down entire planets, though. Anyways, the point of replicators is small-scale use. If you have enough energy to rely on replicators alone then we long have problems. Oh well, if you don't like that word, how about Q-Fabs? They are basically nano-assemblers using modern sintering technology turned up to eleven. You make a blueprint out of forcefields and then "print" the matter on it. Might not be the most economical solution for large yet simple construction but it has the advantage of versatility which means once you have a decent Q-Fab it can build anything from mobile phones to sports cars after just adjusting the program and the required preparation/materials. This and my idea of replicators are similar. The point is that while making stuff out of energy is nice, it's expensive. E=mc^2 is no joke and that's not even talking about other issues. Rather you use raw materials whenever you can because energy is not for free. In general: Traditional construction > Q-Fabs (so long you don't account for versatility thus the latter still dominates in many fields) Raw materials > Transforming one material to another > creating metamaterials > creating matter out of energy Replicators using up metastable matter are a kind of compromise. It works for a simple and not too energy consuming versatile creation kit but metastable matter is not cheap. Its benefits are in the simplification of logistics. Just like how practically every vehicle from ships to airplanes or even tanks within the modern US military uses the same type of fuel. Might not be the most economical but it's an amazing accomplishment regardless. [/quote] Well, to be fair it's not like I just quickly break them down. It's years of constant work to get through a single planet by manipulating gravity to slowly tear it to pieces. Plus we already have one race that has replicators and it's kind of a thing that they're pretty technologically advanced, and they're a bunch of peaceful refugees without any worlds of their own.