After his return to the Disney studio, Iwerks mainly worked on developing special visual effects. He is credited as developing the processes for combining live-action and animation used in "Song of the South" (1946), as well as the xerographic process adapted for cel animation. He also worked at WED Enterprises, now Walt Disney Imagineering, helping to develop many Disney theme park attractions during the 1960s. Iwerks did special effects work outside the studio as well, including his Academy Award nominated achievement for Alfred Hitchcock's "The Birds" (1963).