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3D Animation
The Twelve Basic
Principles of Animation is a set of principles of
animation introduced by the Disney animators Ollie
Johnston and Frank Thomas in their 1981 book The
Illusion of Life: Disney Animation.Johnston and Thomas
in turn based their book on the work of the leading
Disney animators from the 1930s onwards, and their
effort to produce more realistic animations. The main
purpose of the principles was to produce an illusion of
characters adhering to the basic laws of physics, but
they also dealt with more abstract issues, such as
emotional timing and character appeal.
The book and its principles have become generally
adopted, and have been referred to as the "Bible of the
industry."[by whom?] In 1999 the book was voted number
one of the "best animation books of all time" in an
online poll. Though originally intended to apply to
traditional, hand-drawn animation, the principles still
have great relevance for today's more prevalent computer
animation.
The most important principle is "squash and stretch",
the purpose of which is to give a sense of weight and
flexibility to drawn objects. It can be applied to
simple objects, like a bouncing ball, or more complex
constructions, like the musculature of a human face.
Taken to an extreme point, a figure stretched or
squashed to an exaggerated degree can have a comical
effect.[5] In realistic animation, however, the most
important aspect of this principle is the fact that an
object's volume does not change when squashed or
stretched. If the length of a ball is stretched
vertically, its width (in three dimensions, also its
depth) needs to contract correspondingly horizontally.
Anticipation is used to prepare the audience for an
action, and to make the action appear more realistic. A
dancer jumping off the floor has to bend his knees
first; a golfer making a swing has to swing the club
back first. The technique can also be used for less
physical actions, such as a character looking off-screen
to anticipate someone's arrival, or attention focusing
on an object that a character is about to pick up.
Anticipation: A baseball player making a pitch prepares
for the action by moving his arm back.
For special effect, anticipation can also be omitted in
cases where it is expected. The resulting sense of
anticlimax will produce a feeling of surprise in the
viewer, and can often add comedy to a scene. This is
often referred to as a 'surprise gag'.
This principle is akin to staging as it is known in
theatre and film. Its purpose is to direct the
audience's attention, and make it clear what is of
greatest importance in a scene; what is happening, and
what is about to happen. Johnston and Thomas defined it
as "the presentation of any idea so that it is
completely and unmistakably clear", whether that idea is
an action, a personality, an expression or a mood. This
can be done by various means, such as the placement of a
character in the frame, the use of light and shadow, and
the angle and position of the camera.The essence of this
principle is keeping focus on what is relevant, and
avoiding unnecessary detail.
These are two different approaches to the actual drawing
process. "Straight ahead action" means drawing out a
scene frame by frame from beginning to end, while "pose
to pose" involves starting with drawing a few, key
frames, and then filling in the intervals later.
"Straight ahead action" creates a more fluid, dynamic
illusion of movement, and is better for producing
realistic action sequences. On the other hand, it is
hard to maintain proportions, and to create exact,
convincing poses along the way. "Pose to pose" works
better for dramatic or emotional scenes, where
composition and relation to the surroundings are of
greater importance. A combination of the two techniques
is often used.
Computer animation removes the problems of proportion
related to "straight ahead action" drawing; however,
"pose to pose" is still used for computer animation,
because of the advantages it brings in composition.The
use of computers facilitates this method, as computers
can fill in the missing sequences in between poses
automatically. It is, however, still important to
oversee this process, and apply the other principles
discussed.
These closely related techniques help render movement
more realistic, and give the impression that characters
follow the laws of physics. "Follow through" means that
separate parts of a body will continue moving after the
character has stopped. "Overlapping action" is the
tendency for parts of the body to move at different
rates (an arm will move on different timing of the head
and so on). A third technique is "drag", where a
character starts to move and parts of him take a few
frames to catch up.These parts can be inanimate objects
like clothing or the antenna on a car, or parts of the
body, such as arms or hair. On the human body, the torso
is the core, with arms, legs, head and hair appendices
that normally follow the torso's movement. Body parts
with much tissue, such as large stomachs and breasts, or
the loose skin on a dog, are more prone to independent
movement than bonier body parts. Again, exaggerated use
of the technique can produce a comical effect, while
more realistic animation must time the actions exactly,
to produce a convincing result.
Thomas and Johnston also developed the principle of the
"moving hold". A character not in movement can be
rendered absolutely still; this is often done,
particularly to draw attention to the main action.
According to Thomas and Johnston, however, this gave a
dull and lifeless result, and should be avoided. Even
characters sitting still can display some sort of
movement, such as the torso moving in and out with
breathing.
The movement of the human body, and most other objects,
needs time to accelerate and slow down. For this reason,
an animation looks more realistic if it has more frames
near the beginning and end of a movement, and fewer in
the middle. This principle goes for characters moving
between two extreme poses, such as sitting down and
standing up, but also for inanimate, moving objects,
like the bouncing ball in the above illustration.
Most human and animal actions occur along an arched
trajectory, and animation should reproduce these
movements for greater realism. This can apply to a limb
moving by rotating a joint, or a thrown object moving
along a parabolic trajectory. The exception is
mechanical movement, which typically moves in straight
lines.
Adding secondary actions to the main action gives a
scene more life, and can help to support the main
action. A person walking can simultaneously swing his
arms or keep them in his pockets, he can speak or
whistle, or he can express emotions through facial
expressions. The important thing about secondary actions
is that they emphasize, rather than take attention away
from the main action. If the latter is the case, those
actions are better left out.In the case of facial
expressions, during a dramatic movement these will often
go unnoticed. In these cases it is better to include
them at the beginning and the end of the movement,
rather than during.
Timing refers to the number of drawings or frames for a
given action, which translates to the speed of the
action on film. On a purely physical level, correct
timing makes objects appear to abide to the laws of
physics; for instance, an object's weight decides how it
reacts to an impetus, like a push.Timing is critical for
establishing a character's mood, emotion, and reaction.
It can also be a device to communicate aspects of a
character's personality.
Exaggeration is an effect especially useful for
animation, as perfect imitation of reality can look
static and dull in cartoons. The level of exaggeration
depends on whether one seeks realism or a particular
style, like a caricature or the style of an artist. The
classical definition of exaggeration, employed by
Disney, was to remain true to reality, just presenting
it in a wilder, more extreme form. Other forms of
exaggeration can involve the supernatural or surreal,
alterations in the physical features of a character, or
elements in the storyline itself. It is important to
employ a certain level of restraint when using
exaggeration; if a scene contains several elements,
there should be a balance in how those elements are
exaggerated in relation to each other, to avoid
confusing or overawing the viewer.
The principle of solid drawing means taking into account
forms in three-dimensional space, giving them volume and
weight. The animator needs to be a skilled
draughtsman and has to understand the basics of
three-dimensional shapes, anatomy, weight, balance,
light and shadow, etc. For the classical animator,
this involved taking art classes and doing sketches from
life. One thing in particular that Johnston and
Thomas warned against was creating "twins": characters
whose left and right sides mirrored each other, and
looked lifeless. Modern-day computer animators
draw less because of the facilities computers give them,
yet their work benefits greatly from a basic
understanding of animation principles, and their
additions to basic computer animation
Appeal in a cartoon character corresponds to what would
be called charisma in an actor. A character who is
appealing is not necessarily sympathetic — villains or
monsters can also be appealing — the important thing is
that the viewer feels the character is real and
interesting. There are several tricks for making a
character connect better with the audience; for likable
characters a symmetrical or particularly baby-like face
tends to be effective.
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