For investors trying to pick the next fundamental, technological, breakthrough investment, it can be quite the dangerous task if approached foolhardily. The 3-D printing arena has surely been heating up, and if they are thinking of investing in companies like 3D Systems (NYSE:DDD), Stratasys (NASDAQ:SSYS), or ExOne (NASDAQ:XONE), then investors need to answer one very serious question: How much should be allocated toward these stocks? In the video below Motley Fool analysts Blake Bos and Isaac Pino discuss 3-D printing and how investors should determine what percentage of their portfolios should be allocated to companies in this booming sector.

Blake Bos has no position in any stocks mentioned. Isaac Pino, CPA has no position in any stocks mentioned. The Motley Fool recommends 3D Systems and Stratasys. The Motley Fool owns shares of 3D Systems and Stratasys and has the following options: Short Jan 2014 $36 Calls on 3D Systems and Short Jan 2014 $20 Puts on 3D Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.