During the initial development stages of the film, Pixar revisited their work from the original Toy Story and found that, although they could open the old computer files for the animated 3D models, error messages prevented them from editing the files, which necessitated recreating the models from scratch. To create the chaotic and complex junkyard scene near the film's end, more than a year and a half was invested on research and development to create the simulation systems required for the sequence.
