Trope-a-Day: Matter Replicator

Matter Replicator: The cornucopia machine or autofac, which can build matter into pretty much any object that you want and have – or can write – a recipe for.

Sadly, they are required to obey the laws of thermodynamics and conservation of mass-energy.  They also tend to incorporate – especially in larger models designed to build larger objects – arrays of specialized nanofactories and macro-scale tools, and require plenty of energy and specialized appropriate feedstocks for whatever it is you want them to build (so mining, refining, recycling, bactries, and the rest of the industrial supply chain haven’t gone away quite yet).  You can make them increasingly general-purpose in these areas at the cost of greater inefficiency – field autofacs are a lot less elegant and more energy-hungry and expensive to run than standard household models.

Living things generally have to be grown in a medical vat instead; simply because most of them tend to die when only half-printed.  Yes, this is exactly as gross as it sounds.  (Also, some dead organic matter – well, let me put it this way.  While you can print up a steak in an autofac, steak is still made in carniculture vats, because first, self-replicating steak is cheaper, and second, it gets boring eating the exact same steak hundreds or thousands of times.  Similar although aesthetic considerations are why vatwood is generally preferred to directly replicated wood – although vatwood planks are seen as input to larger autofacs.)

Nonetheless, they’re more than good enough for post-material scarcity purposes.