Today we feature
two sections from Chapter 10, Basic Concepts of Animation, A Few New Principles for Computer Animation The twelve principles of animation were created in the
early 1930s by animators at the Walt Disney Studios. These principles
were used to guide production and creative discussions as well to train
young animators better and faster. These twelve principles became one
of the foundations of hand-drawn cartoon character animation. The twelve
principles, as they are commonly referred to, also helped to transform
animation from a novelty into an art form. By applying these principles
to their work these pioneering animators produced many of the earliest
animated feature films that became classics: Snow White (1937), Pinocchio
and Fantasia (1940), Dumbo (1941), and Bambi (1942). The twelve principles are mostly about five things:
acting the performance, directing the performance, representing reality
(through drawing, modeling, and rendering), interpreting real world
physics, and editing a sequence of actions. The original principles
are still relevant today because they help us to create more believable
characters and situations. They can be applied to almost any type of
animation, even though they work best for comedy. But, some of these
principles require updates, and a few new additional principles are
also needed to address the new techniques and styles of three-dimensional
computer animation. Animation techniques and styles, and the scope of productions,
have changed tremendously since the 1930s. The dominant, almost exclusive,
style of animation then was hand-drawn pose-to-pose cartoon narrative
animation. Today we have more styles including non-linear interactive
videogames and non-narrative music videos. In the 1930s some animation
techniques and capabilities were underdeveloped, camera moves and lighting
for example, or misunderstood: rotoscoping or stop-motion. Consider
too the new tools that have transformed our craft: hand-held cameras,
television, non-linear editing, compositing, motion capture, computer
graphics and procedural tools. Other artforms have greatly evolved since
the 1930s, creating new languages and new principles. It is time to
do the same with animation, it is time to reinterpret and expand the
original principles. We also need to create new additional principles
that address today's new animation styles and techniques. This is our
collective challenge. 1- Squash and stretch, the first principle from
the original twelve, is used to exaggerate the amount of non-rigid body
deformations usually with the purpose of achieving a more comedic effect.
Three-dimensional squash and stretch can be implemented with a variety
of techniques: skin and muscle, springs, direct mesh manipulation and
morphing. It can also be implemented in more experimental ways with
weighting, especially for dynamics simulations, and unusual IK systems. 2- The technique of anticipation helps
to guide the audience's eyes to where the action is about to occur (Fig.
10.2.4). Anticipation, including motion holds, is great for "announcing
the surprise." In three-dimensional computer animation it can be fine-tuned
using digital time-editing tools such as time sheets, timelines, and
curves. More anticipation equals less suspense. Horror films, for example,
switch back and forth from lots of anticipation to total surprise. 3- Staging, or mise-en-scene as it is also known,
is about translating the mood and intention of a scene into specific
character positions and actions. Staging the key character poses in
the scene helps to define the nature of the action. Three-dimensional
animatics are a great tool for previsualizing and blocking out the staging
before the primary, secondary and facial animation. There are many staging
techniques to tell the story visually: hiding or revealing the center
of interest, and a chain reaction of actions-reactions are a couple
of them. Staging can also be aided with contemporary cinematic techniques
such as slow motion, frozen time, motion loops, and hand-held camera
moves. 4- Straight-ahead action and pose-to-pose are
two different animation techniques that yield fairly different results.
In the early days of hand-drawn animation pose-to-pose action became
the standard animation technique because it breaks down structured motion
into a series of clearly defined key poses. In straight-ahead action
the character moves spontaneously through the action one step at a time
until the action is finished. Motion capture and dynamics simulations,
even three-dimensional rotoscoping, are clearly the straight-ahead techniques
of three-dimensional computer animation. They can all be blended intelligently
using channels. 5- Follow-through and overlapping action are
two techniques that help make the action richer and fuller with detail
and subtlety. Follow-through action consists of the reactions of the
character after an action, and it usually lets audiences know how he
or she feels about what has just happened or is about to happen. In
overlapping action multiple motions influence, blend, and overlap the
position of the character. In three-dimensional computer animation a
lot of the common follow-through motions of clothing and hair, for example,
can be animated with dynamics simulations (figure below). The layers
and channels in three-dimensional computer animation software allow
us to mix and blend different overlapping motions from different areas
of the character. FOLLOW-THRU 6- Slow-in and slow-out consist
of slowing down the beginning and the end of an action, while speeding
up the middle of it. A snappy effect is achieved when motion is accelerated
and retarded in this way. In three-dimensional computer animation slow-ins
and slow-outs can be fine-tuned with digital time-editing tools. When
using motion capture techniques for cartoon-style animated characters
it is essential to remind performers to do slow-ins and slow-outs. The
inverse variation of this effect, a fast-in and fast-out, is often times
seen in TV commercials and music videos where the beginning and end
of the sequence are accelerated while the middle is slowed down giving
it a surreal or dreamy feeling. 7- Using arcs to animate the movements
of characters helps achieve a natural look because most living creatures
move in curved paths, never in perfectly straight lines. Non-arc motion
comes across as sinister, restricted or robotic. In three-dimensional
computer animation we can use software constraints to force all or some
of the motion within arcs. Even motion-captured performances can be
fine-tuned with curve editors, as long as the motion is not flattened. 8- Secondary action consists of the smaller motions
that complement the dominant action. In three-dimensional computer animation
we can take advantage of layers and channels for building up different
secondary motions, for example, a layer for hair, a layer for the character's
hat, a layer for the cape, and so on. 9- Timing is the precise moment and the amount
of time that a character spends on an action (figure below). Timing
adds emotion and intention to the character's performance. Most three-dimensional
computer animation tools allow us to fine tune the timing by shaving
off or adding frames with non-linear time-editing. Timing can also be
controlled and adjusted by placing each character on a separate track,
and using sub-tracks for parts of the character such as head, torso,
arms and legs. TIMING 10- Exaggeration usually
helps cartoon characters to deliver the essence of an action. A lot
of exaggeration can be achieved with squash and stretch. In three-dimensional
computer animation we can use procedural techniques, motion ranges and
scripts to exaggerate motion. The intensity of a moment can be increased
with cinematography and editing, not just with performance. 11- Solid modeling and rigging, or solid drawing
as it was called in the 1930s, emphasizes the clear delineation of shape
necessary to bring animated characters to life. Solid and precise modeling
helps to convey the weight, depth and balance of the character, and
it also simplifies potential production complications due to poorly
modeled characters. Animation rigs are at their best when they are optimized
for the specific personality and motion of the character. Pay attention
to silhouettes when aligning characters to the camera. SOLID MODELING AND RIGGING 12- Character personality,
or appeal as it was originally called, facilitates the emotional connection
between character and audience. Characters must be well developed, have
an interesting personality, and have a clear set of desires or needs
that drive their behavior and actions. Complexity and consistency of
motion are two elements of character appeal that can be easily developed
with three-dimensional computer animation. Writing down the ways in
which the character moves (Fig. 10.5.7), how he/she reacts to different
situations, and how he/she relates to other characters can help define
the main characteristics of the character's personality. Fine-tune the
personality with the key poses and the character turnarounds. A few of the new issues that need to be addressed by
new principles of three-dimensional computer animation include: visual
styling, blending cartoon physics with real world physics, using cinematography,
mastering facial animation, and optimizing user-controlled animation. 13- Visual styling in three-dimensional computer
animation means more than just how things are supposed to look. Visual
styling also has a significant impact on rendering, on animation techniques,
and overall production complexity. As we develop a visual look we must
keep in mind that it is feasible to produce within the boundaries of
the project. A certain look for the skin of a beast, for example, might
look cool but might also require too complex a rig, too detailed a model
and too complex an animation process. 14- It is possible today to blend motion
from different sources, and we need to develop a clear approach for
blending cartoon with realistic motion. Before production starts it
is necessary to define clear guidelines for a variety of motion/animation
styles including cartoon physics, realistic cartoon, realistic human
motion and rotoscoping. Above all, we must direct live performers when
capturing their motion to add intention to their movements. 15- Since we have absolute control over camera
positions and movement in three-dimensional computer animation, we should
make the cinematography a crucial component of our animation,
not just an afterthought. The composition, lighting, and sequencing
of our moving images has a huge impact on storytelling. Most of this
work can crystallize during previsualization and the assembly of the
three-dimensional animatics. The lighting style needs to be addressed
separately, since it impacts both the look and the rendering pipeline. 16- Most of the thoughts and emotions of characters
are expressed on their faces. Three-dimensional computer animation offers
more facial animation control than ever before, including the
subtle motion of eyelids and eyeballs. Establishing early in the process
the level of facial control and techniques has a positive effect on
the styling of the character and the design of the production flow.
Building a catalog of facial morph targets or blend shapes for production
and reuse is today as essential as building walk cycles. 17- Computer and platform games put much of the
animation control in the hands of gamers. This poses the challenge to
create great animation that works regardless of what move the gamer
decides to make. Games are a combination of user-controlled animation
and preset/narrative animation. One of the creative animation challenges
is to find a balance between the narrative and the improvisational aspect
of the game. Look at the model of participatory street theater (different
from traditional stage theater) for ideas on how to constraint the gamer-action
to establish strong staging. User-controlled animation relies on strong
animation cycles with built-in anticipation that are able to branch
smoothly into reaction shots. Fortunately many of today's game engines
have built-in intelligence that can smooth transitions between animation
cycles. The combination of preset and dynamic user-controlled cameras
is also unique to games.
of "The Art of 3D Computer Animation and Effects," Third Edition.
© Isaac Kerlow. All rights reserved. Not to be
reproduced without permission.
Applying the
Twelve Principles to 3D Computer Animation
Drawings by Steve Rittler
A
Few New Principles for 3D Computer Animation
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