There are mainly two approaches to animation that are used by Animators. The first approach mostly known as Straight Ahead Action, because the animation is actually working straight ahead right from the first drawing in the scene. The second approach is the Pose to Pose method, because each pose in an animation is planned in advanced in order to create a more believable staging action.
Straight Ahead Action
There are mainly two approaches to animation that are used by Animators. The first approach mostly known as Straight Ahead Action, because the animation is actually working straight ahead right from the first drawing in the scene. Doing frame after frame, until he reaches the end of the scene getting new ideas as he draws.
The point of the story is already known and the staging that needs to be done, but he has little plan on how it will turn out in the end since the time he starts drawing the first frame. The drawings and the actions are new, looking great as the animator keeps the entire process intuitive and creative.
Pose to Pose
The second is called Pose to Pose. In this method, the animator plans his character's action and figures out which drawings will be needed to be drawn in order to animate the scene or action. The drawings in this method are related to each other in both size and action. This method also helps the in-between animators fill in the gap of the action knowing what the outcome of the action would be. Such scene is always easy to follow and works greatly because the relationships and foundation has been carefully planed before.
Most of the time in this method is mostly spent on improving the key drawings and create a better control on the character's movement. With Pose to Pose principle method, there are both transparency and control. In Straight Ahead Action principle method, there is spontaneity in the character.
Both methods are still used to this day because each of them offer a certain strengths and advantages for different types of actions in a scene. Sometimes they are even combined by the animator who draws the scene, in such away that keeps the Straight Ahead Action controlled.
A scene is planned in advanced, than the animator would create a rough sketches that portrays the character's progress in his action; although the rough sketches will not be used in the real animation production, they serve as a guide for the character's width, height, position, attitude, relationship with the backgrounds and foregrounds.
They offer much control over the scene even though some animators feel that over-control leads to a still character that is not spontaneous and live. They say that 'An animator should discover the outcome just as his audience'.
Acting requires different approach than a matched background that is not moving and the character should do something with it. Acting requires the animator to plan his character's actions. For example, if a character seems unhappy, it would lower its shoulders, turn around, lower its head and walk slowly with a sad face. This must be done with a Pose to Pose method because each frame must be drawn carefully for maximum clarity, appeal to the audience.
Each frame would than be worked individually and separately and sometimes together until they mimic the action efficiently as possible. Once the poses relate to each other, it is a simple matter to time the frames to create a believable playback animation.
Another element an animator need to take into consideration when choosing the animation method is "texture". A series of actions all with the same amount of intensity and movement in the character will become tedious to draw and predictable during playback. There will be zero punch in the poses. But if the overall work flow contains few other elements such as smooth animation, timing, short burst of moves, accents or surprises the entire thing will become a wonderful animation during playback. This is possible to create using the Straight Ahead Action method.
Using Pose to Pose for "Texture" animation, the entire texture can be planned in advance and the actions could be designed to make the entire statement of the character.
The first animators who used Pose to Pose method were interested in a quick results, and did not realize of its amazing potential in future animation process. They were focused with the position of the character than any entertaining actions of the character. The process would be for them very linear "Go there, than pick up stone, look at stone, throw the stone and run." when handled with such way for animating the character, with no attempt to relate between the poses, the scene were bound to be flat and predictable.
It wasn't until the development of stronger poses, timing improvements, and skillful use of Secondary Action and finally the use of the Moving Hold that Pose to Pose animation method would ultimately became the animator's best method.