Investors in stocks related to 3-D printing have been mostly happy over the last few years. 3D Systems (NYSE:DDD), Stratasys (NASDAQ:SSYS), and The ExOne Company (NASDAQ:XONE) have all soundly beaten the S&P 500 over this time frame:

^SPX Chart

^SPX data by YCharts

But 3D Systems lowered profit guidance in early February, and the industry has been on a downtrend in 2014. Is the great 3-D printing run finally out of ink?

^SPX Chart

^SPX data by YCharts

James Woodcock -- group editor for the highly respected TCT Magazine + Personalize -- has been following the 3-D printing industry for decades. Motley Fool analyst Rex Moore was able to meet up with Woodcock at the 2014 International CES in Las Vegas and chat with him about all things 3-D.

In this video, Woodcock discusses the growing trend on the consumer side, as well as what investors in 3D Systems, Stratasys, and ExOne should watch for to make sure industry growth is keeping up with the share prices.

A full transcript follows the video.

Moore: I had asked you about some trends you're seeing and you mentioned you're really surprised with the consumer side.

Woodcock: Absolutely. Obviously, at CES you're going to see more of the consumer-focused announcements, but even at EuroMold, which is a big industry show in Frankfurt dedicated to manufacturing technologies, the pull from the consumer end has really informed how a lot of these companies are responding to the marketplace. They're not pushing it so much as it's being pulled, and I think that's a really important consideration as the industry grows. I think we will continue to see more of that pull.

People want these technologies, and they're now getting to the point where they are happy to buy them and use them, as a home user, without having the hobbyists where they like to tinker and take it apart. That's not how consumers really want to get into this technology. They want to buy, click and play, and start printing. And now they can.

Moore: Because of the huge growth in this industry, 3D Systems, Stratasys, ExOne; they are all hugely popular with investors. If you're an investor, what should you keep an eye on to make sure that, really, the growth is keeping up with the demand here for the stock?

Woodcock: In terms of the guys that are listed now, the big ones are always going to be aerospace, medical, automotive -- and none of those are anywhere near saturation, in terms of how these technologies can be deployed.

There is huge scope in all of them, and we're seeing the willingness from huge companies, the likes of GE Aviation, to really back 3-D printing as a future technology, and as a future manufacturing method.

That will trickle down to the smaller companies, and for as long as the big guys are shouting about it -- which I don't see stopping anytime soon -- I think the likes of X1, 3D, Stratasys, they have fantastic futures ahead of them.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.