Shares of both 3D Systems (NYSE: DDD) and Stratasys (NASDAQ: SSYS) were up, by 16% and 15% over the past 5 days, respectively, but what was behind the jump in this industry? In this video, Motley Fool analyst Blake Bos discusses how 3D Systems beat recent accounting irregularity allegations, which caused its short-term spike, and he discusses some long-term projections for the industry, including patent litigation that we should expect to see, as well as how long we'll have to wait before personal 3-D printers are practical for the home.