YouTube channel Bloop Animation, a valuable resource for artists, has published an interesting little video for those of us who are clueless about the differences between 2D and 3D animation. The demonstration explores what the core differences between the animation styles are, apart from the final visual results.
It's obvious that 2D animation is composed of hundreds and even thousands of different drawings, while 3D is created by manipulating the character via computer. Artists draw 2D figures frame by frame. They come up with key poses, and then draw the frames in between. If something isn't shown on the screen — like an eyeball when a character is blinking — the eyeball doesn't need to be drawn, obviously. That isn't the case for 3D. Every pose, blink and breath is considered and always manipulated by the animator.
A rig and graph editor helps the 3D animator manipulate various "curves" placed along the figure or object (they determine where they go). One body part can have six curves that move it at different angles. Bloop Animation also explains that 2D animations often pause or freeze momentarily. It means the animator skipped a drawing for that frame, because it just wasn't necessary and made sense in the character's narrative. But in 3D, this just doesn't work. The animator creates what's called a "moving hold," which means the character is actually still in motion. That's why you'll often see 3D figures gently moving when standing still, or blinking their eyes — as in the case or something like Toy Story. The idea is that they remain lifelike at all times. Think new Pixar versus old Disney.
The video is a fascinating, six-minute watch that provides a nice introduction to basic animation. The fact that it's easy to understand is even better. Enjoy!