 Toy Story 's script was strongly influenced by the ideas of screenwriter Robert McKee . The members of Pixar 's story team — Lasseter , Stanton , Docter and Joe Ranft — were aware that most of them were beginners at writing for feature films . None of them had any feature story or writing credits to their name besides Ranft , who had taught a story class at CalArts and did some storyboard work prior . Seeking insight , Lasseter and Docter attended a three @-@ day seminar in Los Angeles given by McKee . His principles , grounded in Aristotle 's Poetics , dictated that a character emerges most realistically and compellingly from the choices that the protagonist makes in reaction to his problems . Disney also appointed Joel Cohen , Alec Sokolow and , later , Joss Whedon to help develop the script . Whedon found that the script wasn 't working but had a great structure , and added the character of Rex and sought a pivotal role for Barbie . The story team continued to touch up the script as production was underway . Among the late additions was the encounter between Buzz and the alien squeaky toys at Pizza Planet , which emerged from a brainstorming session with a dozen directors , story artists , and animators from Disney . 
