PRINCIPLES OF ANIMATION – Overlapping action, Ease in Ease out and Arcs


I am currently studying the next 3 principles of animation, we are looking at 3 together as they are closely linked and difficult to show examples in isolation. It was suggested that I study Richard Williams’ “The Animators Survival Kit”, pages 48 to 60 deal with these 3 principles.


This is where several similar techniques are used together to render the movement more realistic, and that the character adheres to the law of physics. For example two parts of the body may move at different rates/times. For example a person with a very large stomach, the stomach will start to bounce several frames after the character moves. As with animals that have tails, as a animal jumps the tail will follow several frames later, and as it moves back towards the ground the tail will only follow several frames later. As seen in the diagram below:



The movement of the human body and most objects that move, objects take time to spend up as they do to slow down. Like an arm swinging, at the beginning it accelerates slowly, reaching its fastest point at the extreme (in the middle of the action) before slowing down again to reach its end. For this reason animators make the animations look more realistic by using more frames at this slower point and less at the middle. As shown in the diagram below:

what is ani


Most natural movements follow an arched trajectory, this can be seen in a limb moving, or  thrown ball following a parabolic trajectory. Movement doesn’t follow a semi circle arc, but parabolic arc, meaning that as an object speeds up the arc becomes more flattened and as it slows down it becomes more curved. As seen in the diagram below.

what is ani2

I am going to create an animation that demonstrates all 3 of these principles in action. In order to decide what we were animating we picked “scenarios” from a hat.

I picked out “A long tailed, long necked dinosaur” that is “filled with helium and slowly bouncing along the ground”

The first thing I did was search the internet to find some reference, below are several videos that I found on youtube.

Daffy Duck and the Dinosaur (1939)

Gertie the Dinosaur (Winsor McCay, 1914)

Jurassic Park

My next stop will be to design a very basic dinosaur character and start some animation tests.


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