Finding Nemo and Random number generators
When Pixar wanted to release its 2003 film Finding Nemo for Blu-ray 3D in 2012, the studio had to rerender the film to produce the 3D effects. The studio by then was no longer using the same animation software system, and it found that certain aspects of the original could not be emulated in its new software. The movement of seagrass, for instance, had been controlled by a random number generator, but there was no way to retrieve the original seed value for that generator. So animators manually replicated the plants’ movements frame by frame, a laborious process. The fact that the studio had lost access to its own film after less than a decade is a sobering commentary on the challenges of archiving computer-generated work. But it seems to me to be a great reminder of the difficulties in having statefulness in random number generators.