The concept of key framing is one that has evolved with the animated medium. Historically, animation was created as frames in sequential order, (a throw back to film), but traditional animators began to explore ways in which to break down the execution of a shot into a system more agreeable to creating performance. Thus, the idea of using single frames to denote important parts of a scene quickly become the most elegant way of planning and staging.
Should a character go from happy to sad within the course of a shot, then it is possible to create just two drawings that may then describe this complex change of emotion fairly simply, absolutely spiffy for an initial stage of production. The great thing about working in modern computer animation is that this process is applicable to our digital puppets, so that we may benefit from all the the advances in animated acting and planning that have been done by our traditional peers. So for the sake of this little rambling discussion of mine, let's take key framing to be the significant poses/attitudes that define a shot, rather than the software definition of a value of a variable at at one frame in time. (It's a bit confusing, but to the computer, every knot on a curve is a key frame, but we're way more creative that that.)
Key framing has many advantages over the straight ahead, layered approach. What are they, I hear you ask? Well, I'm about to tell you!
As was mentioned above, key framing allows us to plan our work in broad strokes. We can consider the emotive or physical beats within a shot and define them, either by quickly thumbnailing/reference or at the computer/drawing table. If we can create strong, effective key poses, then they should be able to accurately communicate to an audience just what the shot will eventually feel like when it's complete.
Another advantage, and this is huge for professional animation, is that with only a couple of keys it is possible to begin a dialogue with peers or creative superiors. Working to deadlines means that it is imperative that ideas be conveyed quickly and clearly in order to get feedback, so that the shot can progress. The layered approach suffers here, as it is impossible for a director to judge the success of the animator's vision if, (for example), they've only completed some beautifully moving hips and legs, leaving the arms and face for later. Also, should we head off in the wrong direction, it is really easy to go back and rework key poses to be more in line with creative direction. Everybody wins!
The second question in the heading there is a bit of a technical consideration, I think. While it's important to the final polish of a shot, within the context of this discussion I believe the question should be more about good key framing rather than smooth.
Good keyframing comes from the ability to analyse the intent of the shot and distil it to its essence. This could be a subtle gesture or a big, broad action, the process is the same. Once we have this essence we may explore it to come up with suggestions as to how we may convey the intent of the shot in as appealing and simple a way as possible through our poses.
Getting in character, be it by acting or looking at reference or doodling on a scrap of paper is central to finding these keys. This is because empathy brings results! I find that I usually have an abundance of ideas simply by attempting to go through the same experiences to those of the character I am trying to portray.
So now we've learned a little about what key frames are, and how to find the tricksy little scamps. By empathizing with our characters and mimicking their thought process, we can stumble across cool animation choices that would otherwise be hidden to us. Questioning these choices can then help us whittle them down to the best key poses we can add into a scene to most clearly convey our intent to our audience.
It's an exciting and creative time during the creation of an animated piece of work, this 'ere keyframe selection process. Let's go and find some!
Guest blogger Kevan Shorey