By Jennifer Pellet

Think of an object—any object, of any shape, even if it doesn't exist anywhere but in your own mind—and imagine being able to create it, in real life, on the spot. This kind of creative capability is the ultimate in instant gratification, and the best part is, the technology already exists.

Commonly known as 3D Printing (or additive manufacturing), it's a method of building objects layer by microscopic layer, fusing each cross section of molecules until a complete object is formed. The technological process is akin to that used in your average desktop printer, explains Buddy Byrum, vice president at 3D Systems, a 3D content-to-print solutions provider based in Rock Hill, South Carolina. (For more detail about the notion of additive manufacturing, see The Math of Building: Adding or Subtracting?)

"Consider what would happen if you were printing the letter 'A' and the paper got stuck so that 'A' got printed over and over again in the same place," he says. "Eventually the ink would build up, and instead of a flat letter you would create a three-dimensional 'A.' That is essentially what we're doing."

Of course, 3D objects are usually made of materials like plastic and metal rather than ink, and their designs tend to be complicated, but the technicalities of input materials and output mechanics are by no means futuristic sci-fi.

The process begins with a 3D data file no different from those used in traditional manufacturing. These files can be generated by one of many computer modeling software design tools, such as the computer aided design (CAD) software widely used by professional designers and engineers, or the growing body of more user-friendly software geared toward consumers.

Of course, not every object needs to be designed completely from scratch. There are two ways to sidestep the design process:

1. For common objects, just download a design file from an online library, and modify it or print with it.
2. Scan an existing object with a 3D scanner, a relatively compact device that analyzes real-world objects and gathers the data necessary to print them. 3D scans of objects can even be commissioned from service companies for as little as $50.

"Twenty years ago, CAD software would have cost you at least $100,000, and you needed an engineering degree to use it," says Byrum. "Now you can get a capable CAD software system for $1,000, or any number of less sophisticated, lower-cost mechanical design tools suitable for non-professionals."

Once you have a 3D file ready to print—whether you created it yourself, downloaded an existing design, or scanned an object—the data file is fed into a 3D Printer, which prints the object, layer-by-layer, using one of several different methodologies:

Powder-Based Process: This process involves fusing material—particles of plastic, metal, gypsum, ceramic, or glass powders—in a granular bed. In an "inkjet" version of this method, a thin layer of powder is spread in a container bed, and an ink-jet style printer head passes over the layer, depositing a binding substance that causes solidification wherever it hits. This process is then repeated to build the object, millimeter by millimeter. The unbound powder remains around the object, providing support until it is finished, after which the object is extracted from the powder in the same way you would fish a toy out of a sandbox. Another powder-based method, known as selective laser sintering, uses a laser to heat and melt each layer of the powder, fusing it to form the part. (Read the accompanying article The Math of Building: Adding or Subtracting?)

Plastic Jet Printing Process: Also known as fused deposition modeling, this type of 3D Printing employs extrusion, or running a plastic material through an extruder head—imagine a caulking or glue gun—to draw each layer of the object.

Photopolymerization: This process involves exposing liquid polymer or plastic to light. In one such process, known as stereolithography, UV light is projected onto a vat of UV-curable liquid polymer to solidify the targeted portions in small increments. When the object is finished, the unexposed liquid is drained from the vat. Another method of photopolymerization employs multiple jets—one that emits a photo-curable plastic, which is hardened by a UV light beam, and another that prints wax that supports the object during production. After completion, the finished object is heated and the wax melts away.

Variations on these—and even newer—methodologies continue to be developed, notes Behrokh Khoshnevis, professor of Industrial & Systems Engineering and Civil & Environmental Engineering at the University of Southern California. He adds that the right method for your needs depends on a variety of factors, from the desired quantity to the ultimate application.

"For example, the laser-based machines are all more than $100,000, but they're far more accurate so they tend to be more appropriate for building functional parts," he says. "But if you're just building a prototype and don't need to worry about functionality, an inkjet machine is fine."

Still, 3D Printing is clearly a game changer. It lets manufacturers bypass time-consuming steps in traditional manufacturing processes, such as building machine tools and product molds, and enables them to manufacture small numbers of highly customized products. The technology is already being employed in the automotive and jewelry industries. (See Is 3D Printing Road Ready? for more on the former.) Also read more about the medical industries with our article, Printing A Medical Revolution.

"The price of the machinery is coming down, and the quality and speed is going up," notes Khoshnevis. "Eventually these machines will be cheap enough that a lot of people will have one in their home. Ultimately, this technology will revolutionize manufacturing-as well as what can be made at home."

Jennifer Pellet is a regular contributor to Entrepreneur and Chief Executive magazines, writing about personal finance, leadership, and business strategy for a wide range of publications, including New York, Working Mother, and CFO. Jennifer also creates, writes, and produces financial-services-oriented custom content for Time Inc. Content Solutions and Dow Jones Custom Publishing.