Just like Severus Snape, Hugh Murray,IMAX’s senior vice president of film production,presented an ambiguous figure in the Harry Potter DVD Boxset universe. Would he be an unexpected hero — or just another 3-D bad guy?

Hugh Murray performed his dark arts as the stereographer on “Harry Potter and the Deathly Hallows — Part 2,” guiding and filtering the 3-D conversion process for director David Yates. The stakes for Murray and Yates were high; the finale film in the Warner Bros. eight-film adaptation of J.K. Rowling’s “Potter” epic was the first to be released fully in 3-D, and the demands of history — not to mention muggle fans all across the globe — put plenty of pressure on the team.

“It’s always interesting and scary,” Murray said, “to wait and see what the world thinks.”

The world seems pretty happy. The movie was released July 15 and is now north of $900 million in worldwide box office and top critics have adored the film, with many of them praising the 3-D in particular as “outstanding,” “subtle,” ”the finest I’ve ever seen” and a “substantial and organic part of the film.” Not everyone agrees, of course. Roger Ebert wrote that the film is appropriately “dark, gloomy and filled with shadows,” which makes 2D a better option considering the image-dimming that is a side effect of 3-D conversion; Peter Travers of Rolling Stone weighed in that 3-D was simply unnecessary amid the film’s larger triumphs.