system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How much of a Pixar/Dreamworks movie is actually drawn by a human?

I never really understood what the work of the computer is. Are there algorithms for locomotion, gravity, fluid mechanics, etc., or are these things drawn directly on the scene by an artist?

Basically, is creating a Pixar scene closer to drawing in Paint or designing a video game?
gpt
> Are there algorithms for locomotion, gravity, fluid mechanics, etc.,

Yes!

> or are these things drawn directly on the scene by an artist?

Animators place the 3-D models into scenes and define how they move, then the computer actually animates them.

Some scenes, like characters moving, are practically animated entirely by hand - because there are no algorithms to get across certain movements.

Sometimes the "real" equations for things like, e.g., gravity or magnetism aren't as much "fun". Animators sometimes come up with their own algorithms for these things that look real enough to be believable, but maybe a bit cartoony.

One example is Rapunzel's hair - the animators tried using real gravity and real physics of motion but her hair would have been too heavy and unwieldy. So they gave it physics of its own that looks beautiful even though it's not realistic.