PASADENA, Calif. — Sometimes a particular piece of plastic is just what you need. You have lost the battery cover to your cellphone, perhaps. Or your daughter needs to have the golden princess doll she saw on television. Now.
In a few years, it will be possible to make these items yourself. You will be able to download three-dimensional plans online, then push Print. Hours later, a solid object will be ready to remove from your printer.