The U.S. Patent and Trademark Office in Alexandria, Va., recently hosted a fascinating display of technology. 3D Systems (NYSE:DDD), Stratasys (NASDAQ:SSYS), and other top companies involved in additive manufacturing, or 3-D printing, displayed their wares in the same room.

Fool analyst Rex Moore was at the conference, and chatted with Stratasys engineer Jim Comb. In this installment of our multi-part series, Jim explains why expiring patents are benefiting the entire industry, as well as consumers the world over.