The tech industry's latest trend has a lot of different faces -- and some of them are pretty strange.

There's no denying that 3-D printing has taken the tech industry, and Wall Street, by storm. The sector's most recent IPO, ExOne, immediately became a market darling, jumping 13% just in its first day.

For all the hoopla over this new technology, few seem to know exactly how it works. In truth, there are a myriad of different procedures that fall under the umbrella term of "3-D printing," and they range from the self-explanatory to the downright mind-bending. Here's a look at the many facets of this disruptive new technology, and an overview of how it could rank as an investment.

The simple
Let's start off with the easiest concepts and take baby steps toward the weird ones. The most basic definition of 3-D printing -- also known among industry snoots as "additive manufacturing" -- is creating a fully formed object, based on a two-dimensional reference image, by placing layers of substance on top of each other.

The substance in question tends to vary. Some companies create their own powder-and-glue mixture for layering, while others use glass and sand, and others still use filaments of plastic material, also known as fused deposition modeling, or FDM.

Stratasys (NASDAQ:SSYS) has snagged the trademark to FDM technology, and the company creates some of the cheaper 3-D printers on the market, with prices starting at around $15,000.

Stratasys took to Wall Street in 1994, and within the past few years its financials have taken some impressive leaps. Since 2009, the company's most recent trailing-12-month revenue has gone up 91%, and its margins have shot up accordingly. Operating profits as a percentage of sales have risen from 6% to 18%, meaning the company is getting better at creating this new technology at a lower cost of production. Net income has also risen from 4% to 13% of sales over the past three years. Being the first mover In putting a trademark on a buzzworthy technology, Stratasys struck right while the iron was hot and is starting to reap some benefits. 

The straight-up science-fiction awesome
We now know one way 3-D printers can work. But there's more than one way to skin a cat (or print one, for that matter), and this next technique takes the process to a whole other level.

Stereolithography sounds insanely complex, but it really isn't. The technical definition: An ultraviolet laser builds layers out of photopolymer resin to create an object. The Foolish definition: A laser hardens a liquid into layers that stick to each other, forming a 3-D shape. Videos of this technology look like they're straight out of a sci-fi flick, and the end result is a high-quality, intensely detailed object.

3D Systems (NYSE:DDD) is the company behind the Viper line of stereolithography apparatuses, a.k.a. SLAs. These devices produce the most detailed 3-D printing around, and the company's performance on Wall Street has had the same high quality.

Annual sales have risen an extraordinary 185% for the company from 2009 to the most recent trailing 12 months in 2012, and 3D's margins have taken equally impressive leaps. The company's operating profit as a percentage of sales jumped from 2% in 2009 to 16% in 2012 -- the company was able to keep its R&D and SG&A expenses relatively under control, even as its revenue skyrocketed. Net income took a similar jump from 0.9% to 11% of sales within the past few years.

3D's only catch? Its P/E of 87.42 is light-years away from the 15.13 industry average of diversified machinery. That either means the company is way farther ahead of the rest of the pack, or it's overblown by market sentiment. Either way, it's still a hot stock to watch.

Covering all the angles
Many have compared the 3-D printer to the Apple computer. Both technologies boggled the mind when they first appeared, and one didn't stop until it had burrowed itself into the cultural lexicon. Whether 3-D printing takes over the world or not, it's still an exciting industry for investors to watch. The technology is disruptive, and thus far, the companies have retained their earnings and boosted operational efficiency, all while their income continues to soar.