It’s not surprising that 3-D printing has captured the imagination of so many technologists. Create a digital design file or download one from numerous sites now on the Web, adjust a few settings, hit “Make,” and a machine will slowly print the thing, precisely depositing ultrathin layers of a material (usually a cheap plastic) until the object of your design sits before you. It’s a function instantly recognizable to any reader of science fiction.

The basic technology has existed for decades: a group of engineers at MIT patented “three-dimensional printing techniques” in the early 1990s. Companies such as General Electric have used additive manufacturing, as industrial versions of the technology are often called, to make prototypes and complex parts for airplane turbines and medical instruments. But the real cause of excitement is the emergence of 3-D printers that are affordable for consumers—at least those with a thousand dollars or more to spend.