Ang Lee's Life of Pi is one of the most anticipated movies of the year. Mr. Lee's vision, coupled with stunning 3D visuals, has turned a novel long thought "unfilmable" into a thrillingly audacious mix of grand storytelling and powerful and provocative themes. In this exclusive piece, he discusses his first foray into 3D filmmaking, and his partnership with James Cameron and Vince Pace of the Cameron-Pace Group, creators of industry-leading 3D cameras.