When ILM started effects work on The Avengers: Age of Ultron, one of their ultimate goals was to completely overhaul the Hulk—and overhaul they did. From sub-mesh layers to giving Mark Ruffalo real-time markerless tracking so that he could experiment with his Hulkly facial expressions, the studio turned what was already a fan-favorite character into an even more realistic juggernaut. Mike Seymour sat down with the men behind the work to see exactly how they made an all-new smash.