The Fundamental Principles of Animation were introduced by Disney legends Ollie Johnston and Frank Thomas and comprise 12 guidelines for making animations more lifelike and engaging. These guidelines are: Squash and Stretch, Anticipation, Staging, Straight Ahead Action and Pose to Pose, Follow Through and Overlapping Action, Slow In and Slow Out, Arcs, Secondary Action, Timing, Exaggeration, Solid Drawing, and Charisma.

“Straight Ahead” animation involves creating frames sequentially from beginning to end, usually employed for fast or complex movements. In contrast, “Pose to Pose” animation entails establishing keyframes first and filling in transitional frames afterward, often used for emotional or dramatic scenes.

The essence of timing in animation is to lend weight and intention to movements. Whether an action is fast or slow influences how the audience perceives emotion, intention, or the unfolding drama. Timing is also vital for synchronizing physical actions with sound or dialogue.

In-betweening, commonly known as Tweening, is the practice of generating transitional frames between two key images to produce the illusion of motion. While this can be performed manually, many software solutions automate the process.

The frame rate in animation is the frequency at which frames appear every second. A greater frame rate often yields more fluid movement, although it demands more resources for frame creation or rendering. Standard frame rates are 24, 30, or 60 frames per second.

The principles of “Follow Through” and “Overlapping Action” are vital nuances in the broader scope of animation techniques. “Follow Through” refers to the way certain parts of an animated figure continue to move after the figure as a whole has stopped. For instance, if a character suddenly stops running, the clothes and hair may continue to move forward due to inertia. This lends a sense of realism to the animated figure, mimicking the natural physics of motion we observe in the real world. On the other hand, “Overlapping Action” is the subtle offsetting of movements happening simultaneously but initiated at different times. For example, if an animated bird is flying, the motion of the wings would be an overlapping action in relation to the body, providing fluidity and complexity to the motion. Employing these principles effectively can dramatically enhance the viewer’s immersion and emotional connection to the animated scenes. They are generally considered as essential techniques for anyone serious about mastering the art of animation.