Disney copied Disney

Look at this interesting comparison between various Disney animation movies:

That's impressing, the dancing scenes are practically identical between the movies. This is because of the usage of the Rotoscope to create  realistic animation. If nowadays, for making realistic movements in 3d animations, are used real actors that are wearing hundreds of sensors, at that age, the actors were filmed, and then every frame would be drawn by hand. Disney's Snow White is one of the first movies to use this technique.

Another example of rotoscoping is A-ha's Take on Me music video: