More details on Quora: https://www.quora.com/Pixar-company/Did-Pixar-accidentally-d... The ending is sad -- that intrepid recovery mostly didn't end up used: And then, some months later, Pixar rewrote the film from almost the ground up, and we made Toy Story 2 again. That rewritten film was the one you saw in theatres and that you can watch now on Blu-Ray.
I think we made How to Train Your Dragon three times at DreamWorks. So many rewrites, director changes, character redesign, etc. If you ever wonder why a feature length animated film can cost over $300 million dollars, this is one reason.
I teach in an animation program. We tell our students over and over that animation is not like the movies: re-=shoots, pick-up shots, multiple take etc are simply not possible. That is why the bloopers reel in Toy Story was so ironic.