Resident 3-D printing analyst Steve Heller recently turned to Twitter to see what questions investors had about 3-D printing stocks. Twitter user William White was wondering what kind of expectations should investors set over the next decade for 3D Systems (DDD 1.12%), voxeljet (VJET), Stratasys (SSYS 1.34%), and Dassault Systemes (DASTY -0.91%).

Being such a huge question, Steve sat down with the head of Motley Fool's industrial sector, Blake Bos, to help investors start thinking about setting their long-term expectations in an industry that's sure to rapidly change over the next decade. One point the two highlight is how investors should watch competing 3-D printing technologies to see which one becomes the most popular in the future. Check out the video segment below to get the full story. (The relevant segment can be found between 6:49 and 10:17.)