babayaga wrote:

In several points in the main rulebook, as well as in Sunward (in particular, in the section about Venus), it's kind of implied that a cornucopia/fabber can only make stuff that can fit into its internal volume. If you want to make larger stuff, you have to make the pieces and *manually* assemble them. To me this seems unrealistic. Can't the cornucopia just make a *self*assembling* item larger than the cornucopia itself? Or just a protean hive? Sure, the smaller the cornucopia, the longer the process, but I fail to see why the "X can only make items smaller than X" rule should hold.

In some ways I agree with that. Simple fabrication processes of simple items should be able to "extrude" an item that exceeds one dimension of the Fabber. The Spindle (p.333) is an example from the game. Rebar and wire would be some real world examples. In the case of more complex items and processes I think that they probably need to be fully contained. The manufacture of a Sniper Rail-gun for example. I think that nano-fabricating at this level of complexity is likely to require several--if not hundreds-- of different types of nano-machines; some that build magnets, some that build batteries, some that build carbon frames, some that build silicon or optical circuitry. So the fabber isn't just building your item it's building the bots that build your item and the bots that support/feed those bots. Also, many of the processes, (precisely arranging carbon and metallic molecules for example), would need to happen in controlled environments. A little bit of the wrong element floating around loose could really fuck up the whole plan. In many cases waste heat and ambient temperatures around the process is going to be an important factor. Even though it's nano-facturing basic chemistry will still apply and that makes things a lot more complex than a nano-sized child building a tower of nano-sized legos. (At least that's my current understanding.)