The Featured section of Thingiverse, for example, includes customizable iPhone cases, a water bottle with cap, a model of the Winterfell castle from the opening credits to "Game of Thrones" and a "steampunk" version of one of the ghosts from "Pac-Man."
Both fun and useful applications, but not exactly cheap compared to the competition. High-end iPhone cases from companies such as Speck top out around $40. And even a stainless-steel vacuum-sealed thermos bottle sells for just $49.95 from REI. You'd have to make a lot of Thingiverse products to pay off the cost of the 3-D printer and the plastic spools you feed it — to say nothing of the time you invest.
Beyond doodads, a MakerBot can produce "revolutionary" things, as Pettis calls them. His favorite example is the Robohand — a prosthetic for children who were born without fingers. Two makers — one in the U.S. and one in South Africa — collaborated online to create the design. Anyone can download the design and print the components to make the prosthetic.
But very few people need to replace a missing hand — certainly not people in every home. [See video: 3D Printing: From Doodads To Prosthetic Hands]