Overlapping action is the proclivity for distinct character sections to move at different speeds or to continue moving after the character has stopped.
Follow through, and overlapping action is one of the twelve basic principles in animation identified by Disney animators Frank Thomas and Ollie Johnston in their authoritative 1981 book on Disney animation, The Illusion of Life. Drag includes dragging a character’s feet to indicate weight when they stop moving or swing back after stopping suddenly; it can also include other physical actions like hair flowing while walking at high speed.
Artists create animation with a great deal of intricacy, but one key technique animators use to create an engaging scene is overlapping action. When a character moves across the screen, some parts of their body move before or at different rates than others. During the animation, there are always leading and following elements in motion — some moving faster while others follow behind slowly; this gives life-like complexity to a movement that viewers will appreciate.
How to create overlapping action
Unlike in cartoons, our bodies don’t move all at once. So as one part of the body stops moving (such as an arm), another piece might continue to follow through with its motion until it settles down a bit later on. An animator creates this overlapping movement by completing that scene with the hands falling into place even after the character has stopped.
Where animators use overlapping movements
Animators use overlapping animations in a multitude of animating pictures.
The animation uses symbols, called action lines or movement lines, to emphasize a character’s pose and help viewers understand what’s happening. When an animator wants anticipation before motion begins, they will often draw some line that starts from their body part closest to where it is moving toward the endpoint first.
For instance, if someone wanted you saw take off running at full speed as fast as possible, then a series of these types would occur in quick succession ahead of them with each one. These lines of overlapping action start closer towards your feet until finally, all four are showing beneath your legs, indicating those limbs have left the ground, meaning you’re now sprinting away like crazy.