All we can say is, Start designing your fembot today, because “3-D printers” are real and they’re coming soon.

The term 3-D printer is just another word for nothing left to lose. Sorry, too much American Idol. It’s another word for rapid prototyping machine, or fabrication machine, which often gets shortened to just fabber. It’s nice to have choices.

They range from fridge-sized commercial models to 18-inch personal versions. Most resemble the monsters in Attack of the Killer Dot-Matrix Printers, if that were a movie, with “print heads” that slide back and forth on a bar positioned above a fixed surface.

As with ink-jet printers, a device on the print head deposits ink onto the surface below. But the deposition tool can also move up and down, allowing it to spray layers of ink on top of each other.

Replace ink with other materials and it gets really interesting. The ink dropper is a syringe, which can be filled with ceramic plasters, soldering paste, metallic alloys, silicone, hot glue, epoxys, even edible frosting. These are “printed” into layers and used to build… lots of things.

How does the printer know what to build? This is the best part: that’s up to you! Using a Computer-Aided Design (CAD) program, you create a 3-D model of the shape. Load the raw materials into the printer, click the “Print” button, and watch as your brainchild materializes before you.

E-mail your CAD files to other people and they can print out objects that you’ve designed. That’s the idea behind eMachineShop (emachineshop.com). Download the free software, design something, then e-mail the CAD file to them. They manufacture your creation and ship it to you. Need a hard-to-find car part or a saxophone mouthpiece? Have a cool idea for a doorknob? Design it yourself and have one custom-made!

If that sounds like fun, you might want a personal 3-D printer. Check out fabathome.org for links to printers, kits for making them yourself, software, and building materials. There’s even a library of designs from other users, so you can start building frisbees, watchbands, and custom iPod cases right away. Entry-level machines cost less than $3,000.

The layering process is called additive fabrication. Some machines use blades or lasers to carve objects out of vinyl, copper, wood, acrylic, or other materials. This is subtractive, like sculpting. Machines start with a block of metal and cut away everything that doesn’t look like a doorknob, for example. Both methods are combined to create complex products, like circuit boards and precision electronics.

Neil Gershenfeld of MIT's Center for Bits and Atoms is helping to bring “fab labs” (fab.cba.mit.edu) to far-flung places “beyond the reach of conventional technology devel-opment.” As the machines in these labs shrink in size and cost, people will be able to create products at home. This could usher in a new era of creativity and commerce, just as the rise of the Internet did before. A Wired magazine article at tinyurl.com/doa56 examines the possibilities.

So the next time you have a million-dollar product idea, write it down and wait for the ap-proaching day when you’ll have a 3-D printer in your home office next to your fax machine. In the meantime, I’ll get back to my CAD program and finish designing those two propellers for the front of my fembot. This thing’s gonna look fab-ulous.