When a series of separate sequential images (i.e. flipbook)
perceive them as separate but as a single
blended moving image.
-
due to the physiological
phenomenon known as persistence of
vision
-cinema, TV, games, new media and Internet - are only possible because of this
small quirk in our human ‘visual apparatus'?
4 fps – images seem separate
8 fps – image begin
to blend
11 fps - illusion of
continuous movement
15 fps – much flash , cheap animation and old video games
24 fps – film rate –
all cinema is at this rate
30 fps – tv rate ( interleaved to seem like
60 fps)
>30 fps – new
real-time games
What is our perceived fps –
what is the fps of reality?
Before Muybridge no one thought that way – now we do:
|
|
|
|
|
|
|
24 still cameras linked by trip wires at carefully placed intervals along a race track |
Movies
Edison and gang
thought movies were individual
From coin op movies to group
viewing: NY prejudice and the Jews
A
perceptual paradign shift. Just
like the phone. Inventors and Conceptualizers.
The movie
Industry: 1900 to today
Films were PhotoPlay: Photograph + Plays
Early Film makers were technologists
·
Technology is a media that isn’t fully understood yet
·
Painters where technologist when they had to know the
chemistry of paint
·
i.e. De Vinci and Michelangelo
The Language of Cinema took less than 25 years :
http://classes.yale.edu/film-analysis/htmfiles/cinematography.htm
Still evoving every year
The pov to room establishing shot
Close-ups were thought to be wrong
No longer photo play but cinema
No longer technology but art à
film schools
No long art but reality - the lens flare in games and
animation systems
So the illusion and art of
real is now reality to have in your 3d system.
3D systems have simulate
cameras not eyes – why
Now animation is the new
technology
How long till it’s gets its language
Borrowing from cinema (
just like cinema borrow from photo + plays in the early days)
Your generation will come up
with a new language
Animation is the art of
movement and bring life to – animate
Using persistence of vision
animators create sequence of drawings
What rules
do we base animation on:
Newton
§ Every object has mass (weight) and will remain at its natural state of inertia (i.e. not moving) unless a force is applied to move it.
§ The greater an object's mass (weight), the greater the force that is required to move it.
The really important thing to bear in mind is that when you're animating, although you may know how big or how heavy an object or character in your scene is meant to be, and you may draw or model it accordingly, its size and/or weight is only really made apparent to your audience by the way you make it move or be moved. For example, if a character picks up a box, your audience will know how heavy it is meant to be by how much effort your character is seen to expend in lifting it.
§ Once an object is moving, it tends to keep on moving unless it is stopped by another object, or unless it is gradually brought to a halt by friction.
An example is the car in fig. 1.20. It has reached cruising speed but when it is stopped by crashing into the text, it crunches up not just because of hitting the text but because its back half is still moving forward along the smooth road, even after impact. A ball rolling along a smooth path will keep on rolling much longer than the same ball rolling along a rough path. A heavy object will be slow to get started moving and slow to stop; lighter objects will move more quickly.
Overlapping Action
When
you think about animating any action of anything, you could break it down, like
Fig. 1.22: All
images shown on this spread © Larry Lauria.
Overshoot
Another aspect of starting and stopping is that
objects will generally overshoot their mark before settling back into their
final position. This is an effect that you'll generally use for most objects in
motion. This overshoot is likely to be the default for 3D software animation
but you'll need to override it for mechanical objects or where you don't want
your ball, say, to bounce right through the floor.
Follow
Through
If
you've ever had tennis or golf coaching, you'll remember your coach telling you
to ‘follow through’ after you've hit the ball. By this, the coach meant ‘don't
try to stop the arm movement once racquet or golf club has made impact; allow
natural carry through of movement’.
When animating an action, bear in mind that few movements end abruptly at a given point and objects are usually made up of a number of connected parts of varying weight and type. For example, Superman has tight clothing that would remain attached to his body like a second skin. His cloak, however, although attached to his shoulders, will behave quite differently; it will billow in the wind and come to rest after Superman, himself, has alighted. How far the cloak carries on moving and how swiftly it comes to rest after Superman has landed will depend on the type of fabric (e.g. gossamer light, or heavy velvet) and friction, e.g. air resistance. The same principle applies to the animation of all secondary objects attached to the main object as explained under ‘overlapping action’, e.g. hair or floppy ears.
Squash and
Stretch
You're
probably familiar with this animation concept from Disney characters. They have
a rubbery, elastic quality when they move. Animation is the art of exaggerating
movement for dramatic and comic effect. The principles are simple: when an
object hits something, it squashes and when it rises, it stretches (figs
1.20–1.25). This is standard animation practice for 2D and much 3D. Just how
much you exaggerate the effect will depend on the degree of realism you want to
convey.
Fig. 1.23: Application
of squash and stretch for this pencil by Larry Lauria.
All images shown on this spread © Larry Lauria.
Fig. 1.24: Application
of squash and stretch for Larry's Jack-in-the-box.
Slow-in
and Slow-Out
Most moving objects don't begin and end the
movement at full speed. They begin slowly, get up to speed and slow down before
drawing to a stop. Think of a car starting, driving and stopping or perhaps
something that you see constantly on TV station breaks and commercials: a
flying logo. It takes off smoothly and slowly from a stationary position,
gathers speed and spins or flies around before settling gently into its final
position on screen. The bouncing ball demonstrates another type of
slow-in/slow-out (fig. 1.25).
Fig. 1.25: This
demonstrates slow-in/slow-out keyframes for Larry's
bouncing ball (shown by the crosses on the curve). As the ball slows, the keyframes are closer together, i.e. there are more
in-betweens, and vice versa when the ball speeds up. You can also see the
principle of squash and stretch as applied to speed (as well as impact when the
ball hits the ground).
Because
this smooth, slow-in/slow-out type of movement is so common, your software is,
again, likely to use it as the ‘default’, meaning that the software may give
you this type of movement whenever you move an item from point A to point B,
unless you instruct it otherwise. You might not want this type of movement when
you need the movement to be sharper, for example when a lid falls
shut from an open position. The lid would slow-out but, similarly to the ball
hitting the ground, it speeds up as gravity pulls it downwards to its shut
position. Indiscriminate use of 3D software's default slow-in/slow-out motion
gives an unnatural, floating look, so use appropriately and with due care.
Moving in
Arcs
Objects thrown into the air will go up and come
down following a parabolic curve. A ball bouncing demonstrates this curve (fig. 1.25). Move your objects
in arcs – however slight – rather than in straight lines wherever possible, for
example when a character's head turns from one side to the other (fig. 1.27) or, similarly,
when a character's eyes move left to right and vice versa. Even a door opening
and closing follows this principle (fig. 1.26).
Fig. 1.26: Here,
Larry demonstrates how a door swing moves in arcs.
Fig. 1.27: This
simple head turn drawn by Larry follows the same principles.
Anticipation
Character animation is all about timing and
pacing. In order to maximize the drama or comic effect of any important action,
it's important to signal to the audience that something is about to happen
before it actually does happen. That way, we not only gain greatest impact from
the scene but we also allow the audience time to register what's happening to a
character on screen (things happen much faster in animation than in live
action). We need to build in anticipation at all levels from a simple
action such as jumping or reaching for a mug (figs 1.28 and 1.29) or doing a take or
double take when something really shocks or excites a character.
Fig. 1.28: Larry's
drawings of Joey jumping to reach the golden ring demonstrate a number of
animation techniques discussed: moving in arcs, slow-in/slow-out, anticipation,
squash and stretch and overlapping action.
In drawing 1 we see Joey in normal standing position.
In drawing 2 he is anticipating his leap by bending his knees prior to takeoff,
clenching his fists and looking toward his goal with a determined expression.
In drawing 3 he takes off and we see how his body is
stretched as he rises. Note the overlapping action of his hair and clothing at
different parts of the action. When Joey lands, his knees
bend once again before he straightens back into his normal standing position.
Joey is vertically challenged. He must get the
golden ring at all costs!
Fig. 1.29: Grabbing
the glass: anticipation is evident in how Larry has drawn the arm and hand
movements. Notice how the arm bends before stretching out and how the hand
opens (in drawing 3) in anticipation of closing around the glass in drawing 4.
Also notice the balancing action of the other arm.
Takes and
Double Takes
These
are just exaggerated forms of anticipation, e.g. a character walks off a roof,
a mountain ledge or whatever and continues to walk unconcernedly on thin air
until some sixth sense tells him that his feet are no longer on terra firm, at
which point he looks back or down and becomes aware of his plight. He shows us
his reaction (the take) usually by a frozen expression of horror (a ‘hold’) –
before falling very fast to an unhappy end. The double take is a variation when
it takes two looks (the first look doesn't quite register the situation) before
he fully realizes his predicament and falls.
Holds
Holds are deliberate pauses in an action. But
beware! In either 2D or 3D animation, just leaving a character in a static
position, without even an eye blink, can be fatal – literally. Your character
appears to die on screen and may look like part of the painted background. For
this reason, your ‘hold’ should, more often than not, be a ‘moving hold’, i.e.
your character pauses, but some small part still moves: it might just be an eye
blink now and then or a slight shift in position.
How long should a hold last? This is an area where you should experiment, be very self critical and you will gain experience. There are many types of holds, not all for the purpose of dramatic effect. You may, for example, want to show your character looking at something off screen, before cutting to show what is being looked at. The hold on the character in this case should be for about 16 frames (if the running speed of your final video is at 25 f.p.s.) and for a few more frames if you are making a video at 30 f.p.s. Some holds are only a few frames long, e.g. the closed eye position for a blink (see Chapter 7). Normally a hold must be for a minimum of six frames to register that it is, in fact, still.
Force and
Drag
Many
objects, most notably humans and animals, are made up of a series of flexible
joints, all linked to each other (seen graphically in the body of the robot in fig 1.30). In 3D animation,
this is a hierarchical structure, where each item can be termed the ‘parent’ of
the children who are dependent upon it. Take the example of the leg. The knee
is a child of the thigh (the thigh being the parent of the knee, but a child of
the lower torso); the shin is a child of the knee; the foot is a child of the
shin and the toes are children of the foot. When you move the ‘parent’ the
children automatically follow but will lag a little behind the parent. Each
successive child in the overall chain will trail a little behind its parent in
slightly overlapping action. This type of linkage is known as ‘forward kinematics’ (or ‘kinemation’).
Another form of this hierarchy is ‘inverse kinematics’.
This is where the child initiates the movement and all the other links
in the chain follow, bending or rotating according to their natural constraints
which have been pre-set by the animator. Setting constraints for all the joints
is often a lengthy process, but it saves much time in
the long run if the character is, say, dancing or doing some other complicated
action.
Fig. 1.30: Robots
make excellent bodies for linking joints in either forward or inverse
kinematics. These principles are outlined briefly under ‘Force and drag’ and
explained further in Chapter 5. This robot is designed by
Kenny Frankland. Image © Kenny Frankland
2001.
Cycles
Using cycles, i.e. repeats of the same set of
drawings, is a great time-saving device, particularly in the case of
traditional hand-drawn animation. If, say, you want your character to walk past
a house, it takes a great many drawings to have him cross the screen, left to
right with a static background. If, on the other hand, you continually cycle
two steps of the character, making him ‘walk on the spot’ while the background
is panned behind, you achieve the same effect, but a great deal of drawing time
is saved. The same principles can be applied in computer animation: a
repetitive action can be accomplished by copying a given set of frames (e.g.
the eight-frame walk cycle of the little man walking in the top right-hand
corner of this book) to another part of the timeline. One of the great benefits
of computer animation over traditional techniques is that your character no
longer has to ‘walk on the spot’ while the background moves: the computer will
allow him to follow any path automatically, cycling the set of frames over the
path, no matter how winding or complicated. To make a seamless cycle, there
should be a smooth transition between first and last drawings in the cycle.
Keyframe
Animation
In
understanding this term, we firstly need to be aware that time, in movies, is
measured in frames. There are 24 frames per second in projected movie film in
cinemas, 30 f.p.s. in American (NTSC) television and
video, and 25 f.p.s. in European and Australasian
(PAL) TV and video, and often 15 f.p.s. or even fewer
for online animations or movies.
Keyframe gains its name from its traditional hand-drawn origins when the chief animator (being the best artist) drew the ‘key poses’ (or ‘extremes’ of position and movement) of a character at a particular frame number (a given point in time) to mark each major change in a character's position. The in-between artist then filled in all the intermediate (in-between) positions. Your computer is the in-between artist and you are the key animator. Keyframes can be thought of as poses if applied to a character, e.g. each of the numbered images of Joey in fig. 1.28.
In 3D terms, each keyframe will set an object's position, degree of rotation and/or scaling in the X (horizontal), Y (vertical) or Z (depth) axis – at a particular frame number (fig. 1.31) in the timeline, which is measured in frames and seconds.
Fig. 1.31: 3DS
Max screen grab showing section of keyframe for an
animation of a teapot lifting by itself, jiggling and pouring tea before
reseating itself back on the table. The key spots on the timeline indicate the
teapot's position and rotation changes. Image © Marcia Kuperberg
2001.
Staging
and Posing
It may seem obvious that your audience should
notice and understand what your characters are doing on screen. Alas, very
often, inexperienced animators spend much time working on a particular
movement, only to find that its significance is totally lost on the audience.
You need to choreograph the characters' actions so that their meaning is immediately clear to the viewer. This is called ‘staging’ or ‘posing’.
Larry Lauria comes from a traditional Disney-style, craft animation background. These are his guidelines:
1. Posing involves mainly the key poses.
2. Exaggerate the line of action.
3. Look for strong silhouettes which express emotion.
4. Really push your drawings.
5. Look for secondary body elements to assist your posing, e.g. hair, hands, clothing, feet.
Straight Ahead Animation
You may hear this expression, although it is generally
considered to be a less effective way of working than pose to pose. It springs
from traditional 2D hand-drawn animation when an artist may have had an action
in mind and just kept on drawing until the action was complete, i.e. without
first mapping out the key poses. Obviously, even with this spontaneous way of
working you would certainly need to rely on your computer to do the in-betweening for 3D work and for much 2D work, which really
brings you right back to the pose to pose way of working. To try to create each
frame's movement, yourself, in the computer would be
to negate this vital function of your animation program.
In computer animation it's a good idea to get used to thinking of movements as beginning and end changes to the status quo of a character (or object) and these ‘changes’ are, in effect, key poses at keyframes. The really important thing is to create meaningful poses. The stages of creating these are shown in fig. 1.32. If you are working with 3D characters rather than 2D drawings, you may still find it helpful to sketch out the poses to help visualize the action.
