The Rendering Process
Rendering is the process that fills in the rest of the movie. If you have a movie, a 120-minute animated film, no one is going to draw all of it one frame at a time, especially if the movie is intended to be viewed at 60 frames per second (fps). Some big-screen movies are viewed at 60 fps, but most videogames are generated at 30 fps. For purposes of this discussion, we’re going to assume the rate is 60 fps.
If you had a flip book that would be 60 pieces of paper for every second.
If you had 1 second, times 60 seconds in a minute, times 60 minutes in an hour, times 2 hours in a movie, that is a lot of frames. On top of that, this implies that the movie is static - every time you look at the movie, the movie is the same.
The player cannot do something like roll this ball forward and see what is behind it. If the game intends those types of actions, then you probably have the equivalent of two or three 2-hour movies in every videogame.