In 1995, Pixar kicked off the computer-generated animation boom with Toy Story, the first ever full-length cartoon film made entirely on a computer. Before that, the vast majority of animation was drawn by hand, which meant huge teams of artists working tirelessly to draw individual cells of animation.
It was hard work…but it did give us classics like Snow White and the Seven Dwarves, Bambi, and Dumbo.
All that first changed in the late 1980's, when computers finally became awesome enough to create the same high quality product as those hard-working artists. Plus, the new technology could add dimension—literally. Traditional animation could only be done in 2-D, so it always looked flat up there on the screen.
But with computer-generated animation, you could create an animated world with as much depth as a real one. And that's important in a movie that takes place not only in the real world on land, but also deep beneath its blue oceans. Added depth requires, well, added depth.
By the time Finding Nemo came out in 2003, loads of other movies—Antz, Shrek, Ice Age —had already taken the computer-animation baton and run with it. Each successful computer-created cartoon only added to the demand. But, even in that company, Finding Nemo is pretty elite. To this day, it's still one of the highest grossing animated movies of all time.