Utilize the input text as a context reference, choose the right relationship between Stratasys and 3D printing from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

Troy Jensen at Piper Jaffray said that the 3D printing industry is "starting to show signs of reacceleration," with the outlook for Stratasys being more positive than that for 3D Systems.

Answer: product_or_material_produced