For those that don’t know animation software, 3D animated characters typically have to be manually posed using a combination of both interactive pivots and graphed coordinates for every individual one of those pivots, rendered out, then played back in order to get an idea of what the final animation will look like, and you wouldn’t even be able to see his fur. 

Pixar’s in-house animation program, Presto, as demonstrated above, not only plays those animations back in real time, but also plays back with all 3 million strands of Sulley’s fur visible. 

To give you an idea of how much computer memory this takes, Monsters University’s final render, after the lighting process, was 20 gigabytes per frame. There are 24 frames in one second of animation.