But that open-ended question is also a challenge for 3D printing. Do consumers know what they want, and do they care enough and have the patience to make it?

Home devices such as the MakerBot Replicator and print-to-order companies like Shapeways and Sculpteo can take an idea and make it physical — limited to plastic in the former case but extending to ceramic, plaster, stainless steel and even silver in the latter. Still, you must have the idea to start with.

That's no problem for "makers" — the new hip, high-tech name for hobbyists and home inventors.