Piper Jaffray's Q4 reseller survey in the 3D printing space indicates overall system and material demand improved sequentially in Q4 while service bureau demand appeared to be modestly below plan. The analyst believes Stratasys (SYYS) and 3D Systems (DDD) are also participating in this growth and he upgraded both stocks this morning to Overweight from Neutral. Further, the move from prototyping to end-part production is also gaining momentum and this could be a significant and sustainable driver for industry growth, Jensen tells investors in a research note. The analyst believes the upcoming earning season could be a catalyst for the group given the "favorable" Q4 survey results. In addition to the two upgrades, he reiterates Overweight ratings on Materialise (MTLS) and Voxeljet (VJET).