An animator, film historian and professor of animation at the University of Southern California. His movie credits include Beauty and the Beast (1991), Who Framed Roger Rabbit (1988), The Little Mermaid (1989), Aladdin (1992), The Lion King (1994), Osmosis Jones (2001) and Shrek (2001). In addition, TV series such as The Superfriends (1978), He-Man and the Masters of the Universe (1983), and She-Ra the Princess of Power (1985). Winner of the June Foray Award (2011) from ASIFA/Hollywood. He has lectured on animation around the world and is President Emeritus of The Animation Guild Local 839 Hollywood. Member of the Board of Governors of The Motion Picture Academy of Arts & Sciences.
He is the author of several books, including: Drawing the Line: The Untold Story of the Animation Unions from Bosko to Bart Simpson (UK press, 2006), Timing for Animation (2009), and Moving Innovation: A History of Computer Animation (MIT Press 2013).