In this example, one storyboard component that needs to be drawn is a man standing on a rolling ball. He is teetering back and forth. When he teeters back and forth, he can only stand in so many positions. This is about 6 frames that would be worthwhile for someone to draw. Here is the list:
- He rocks forward a little bit
- He is centered on the ball
- He rocks back a little bit
- He tries to regains his balance, maybe a little lower
- He does regain his balance
- He falls off again
You could draw 5 frames and take a frame from the storyboard, or you could draw all 6 frames. These 6 frames are key frames for 1 second of animation. They are the ones that dictate the action. The Key frames are the ones that are "hand-drawn", whatever that means. If you have 1 frame from the storyboard and you get 5 frames from the artists, then you get the other 54 frames from the computer.
Then, when it is time to render this animation, you can set a number that indicates how many frames the computer will draw between key frames. If we have 6 frames in an animation that is 60 frames a second, then the computer will draw 9 or 10 frames between key frames. For lack of a better word, the computer connects the dots between the positions of the important items in the graphic image.
So this man is having a fun time standing on this ball. In a close up you could see his arms waving. We can add some detail to the 6 key frames.
- He waves his arms this way in the front
- He waves his arms back
- He has a little difficulty getting up
- He almost falls over
- He almost touches the ball
- He gets up again
This is a repeating video, a second's worth of animation.
The computer would figure out what those 10 frames are in terms of where the stick man’s hands are and just draw those for you. It is important to figure out what the key frames are, based on the story board, and then let the computer draw the rest of it. Once again, there will be detail that should not be rendered. For example, if the man's feet never leave the ball then there is no need to put a surface on bottom of the tennis shoe.
What makes the animation look lifelike is the ratio between the number of key frames to the number of rendered frames. What the ratio should be is really dependent on the thing that is being created.
The game components will undergo these processes several times. They will be transferred between the rendering process, the story line, the surfacing, and the lighting, and so on from desk to desk until the entire production is complete.