overview
Abstract
2D animation
can only be automated to the extent that the computer acts as
an interactive assistant to the animator. The key problem is
that the 3D information which is implicit in the animated drawings
is unavailable and this has encouraged the view of 2D animation
being a subset of 3D animation in its fullest generality. However,
introducing more than the absolute minimum of 3D information,
essentially that contained in a hierarchy of drawing overlays,
has matching advantages and disadvantages because animators,
for aesthetic reasons, deliberately break the rules of geometry
and physics as they apply to real-world objects. A software
environment which only supports 2D functionality and drawing
overlays is sufficient to promote cost-effectively the full
range of effects that animators use while the state of the 3D
animation art is as yet incapable of this. Essentially the same
techniques can be used on live-capture images once they have
had a structure similar to that required for animation imposed
on them.
Story development
Whether from an original concept or by buying rights to a book,
a story must be developed to fit the proposed duration of the
movie. This in turn will be refined into a storyboard. A storyboard
shows sketches of the envisaged movie, each of which represents
perhaps 4-5 seconds of action, with the dialogue shown against
each picture. A shooting script and a timing chart are also
normally produced.
Model sheets
are also prepared. These show the major characters in different
poses, from various angles and with a variety of expressions.
They will also show the colouring to be used. In effect, the
model sheet is the nearest an animator usually has to a sculpture
of the character. The model sheet is used to fix in the animator's
mind how the character moves and what it looks like.
This completes
the design phase.
Leica test or Animatic
Leica test a somewhat dated term is used for the first attempt
to put together a film of the required length. As there is no
animation available yet, it is filmed from stills corresponding
to the storyboard, but each still is held for as long as the
corresponding sequence will take. A soundtrack will be added
because the animators will work from the timing of the sound,
especially for dialogue but also for overall pace. The result
gives an impression of the movie. Weaknesses can be spotted
and a re-design can take place to rectify them.
Scene
staging
Scene staging is the mapping out of each scene, in particular
the relationship between the characters and the background elements.
The backgrounds may well be prepared in full once this has stabilised.
Backgrounds are those elements, typically scenic, which are
unvarying across many frames and so can be painted in much more
detail than can a character. A good background can give a lot
of visual richness to a scene or can set a mood, as well as
providing the correct context and contrast for the main action.
Backgrounds are often much larger than the frame size, to allow
for pan or zoom effects.
The term `staging' is usually reserved for the development of
the viewpoint the animator is encouraging the viewer to take.
Staging is really the clear presentation of an idea which includes
avoiding anything which might distract the viewer's attention
or placing characters, viewpoints, expressions etc, even the
timing of a scene, so that the viewer's attention is engaged
most directly. This use of the term `staging' really covers
the design issues in setting a scene while scene staging is
about how to implement the design and may involve questions
of how to break down the scene into layers.
Drawing
The next stage is thus to produce the drawings for each cell
in each frame. These are line drawings, not coloured, and were
originally prepared on something which resembles tracing paper
with accurately-located holes for mechanical alignment. In the
computer environment a similar but more accurate process happens.
This is done in three phases. Firstly the extreme drawings are
produced (key frames). These show the major features of the
action and are drawn by the main animator. Next the computer
creates the in-between frames, these then need careful checking
and the motion between the key frames is adjusted to generate
the desired movement.
Key frames
and tween frames can be quite rough, with lots of experimental
over-drawing, and will usually have to go through a clean-up
stage.
Line test
A line test is shot (nowadays often onto video or reproduced
on DVD) without the backgrounds, and still using the line artwork.
The purpose is to verify that the movements are correct and
that characters interact accurately. In some cases, this may
reveal problems and those sections will have to be reworked.
If the line test is accepted, and on film rather than video,
it can then be spliced into the Leica test (animatic), replacing
the corresponding section of stills. The animatic thus evolves
towards the complete movie. Indeed those of us who are used
to computers have to remind ourselves that the product at any
stage is simply the current piece of film: the task of recreating
this from the drawings is much greater than that of splicing
together computer files. At the end of the process, the film
is the totality of what is required: all of the drawings can
be disposed of.
Ink
and paint
The outlines are then coloured. In the computer environment
colour consistency is no longer a practical difficulty: all
characters will have their colours precisely defined so that
they can be mixed in a digital palette. Special paints are no
longer needed either as translucent and other special effects
can now be controlled more accurately within the digital environment.
Rendering
The artwork for each frame is now illuminated and shot within
the computer environment. Some special effects can be added
at this stage but compositing and other effects are completed
post rendering.
Unlike the original rostrum cameras which are physically massive
and only offer limited facilities for moving backgrounds, the
digital camera offers much greater flexibility and control,
it also allows us to try ideas without committing to the final
shot, thus saving time and a lot of money.
Soundtrack 
The final soundtrack is then synchronised with, and added to,
the movie. At the outset, the sound was used to drive the animation
timing: in the end, the fine adjustments needed are made the
other way round.
