HOUSTON--(BUSINESS WIRE)--Changing Technologies, Inc. (OTCBB: CHGT) remains upbeat about user and revenue prospects for its upcoming online 3D printing portal after a recent respected industry survey revealed two-thirds of the Top 100 manufacturing companies are employing 3D printing in their industrial process. “As the survey shows, 3D printing is a robust market that’s only going to continue to grow far into the future,” said CHGT CEO Marco Valenzuela. “We’ve already seen great interest in an