HOUSTON--(BUSINESS WIRE)--Changing Technologies, Inc. (OTCBB: CHGT) is increasingly moving into 3D printing consulting services, offering the firm another important stream of potential revenues and delivering a key differentiator between it and less-experienced outfits. “3D printing can be very time consuming and wasteful if not set up properly and efficiently,” said CHGT CEO Marco Valenzuela. “Every day we see news of someone buying a 3D printer and setting up shop. But our depth of knowledge