3D Systems (NYSE: DDD) isn't the title of a hit summer movie, but it still has the potential to get customers lined up around the block. This company makes devices that can produce three-dimensional plastic, metal, or composite objects by laying material down layer by layer. Think of an ink-jet printer that has the ability to print ever thicker layers of material until a 3-D object appears. I like to think of the company as a digital smithy.

Three-dimensional printers used to be so large and expensive that they were practical only for industrial purposes, such as making product prototypes before being sent out for a full production run. Now, these printers are sized and priced for use by smaller companies for less than full-scale runs of finished products. There are 3-D printers for sale small and cheap enough for the hobbyist. 3D Systems offers one in the $1,300 price range.

The company sees an important use for its products in the medical field. It already supplies 3-D printing systems to dentists for the creation of crowns, bridges, and other dental structures. But how about this use: custom-made body parts. A San Francisco company, Bespoke Innovations, uses 3D Systems' printers to create prosthetic limbs to order.

3D Systems has three divisions: the manufacturing and selling of printers, the selling of materials for use in those printers -- a great source of recurring supply revenue, and the running of service bureaus for a broader group of customers who need only the occasional use of 3-D printing capability.

The company's biggest competitor is Stratasys (Nasdaq: SSYS), which has been around almost as long as 3D Systems but has chosen -- so far, at least -- to stay away from the lower-end hobbyist market. Its cheapest system goes for around $15,000. Stratasys also makes 3-D printers for Hewlett-Packard (NYSE: HPQ), which then resells them in Europe under the HP brand.

3D Systems' 2010 revenues were 31% higher than Stratasys', and its net income was more than twice as much. In all, 3D Systems' financials look to be in decent shape, with free cash flow of $30.5 million. The P/E is on the high side at 37, but for a high-tech company in an emerging industry, that's not unexpected. Stratasys has no debt on its books while 3D Systems does, but it's nowhere near a deal-breaker at 3.97% total debt to assets.

Why buy?
This is a company to buy for growth. Not only is it the leader in its industry, but it invented the industry in 1986, and it's an industry that's just starting to feel its oats. Try this potential application on for size: house construction. A California company envisions using a 3-D printer on a tractor-trailer to layer concrete into walls, which are then assembled into a finished structure. Imagine an architect emailing the blueprints in a computer-aided-design file to the contracting team. They fire up the 3-D printer, and out pops a house. Well, maybe not quite that simple … yet.

But imagine what the future can hold. To stay updated on the future of 3-D printing, add any of the companies discussed here to your Foolish watchlist today.

Fool contributor Dan Radovsky has no position in any of the companies mentioned.

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