Computer-generated imagery (also known as
CGI) is the application of the field of
computer graphics or, more specifically,
3D computer graphics to
special effects in
films,
television
programs,
commercial,
simulators and simulation generally, and
printed media.
Video games usually use
real-time computer graphics (rarely referred to as CGI) , but may
also include pre-rendered "
cut scenes" and
intro movies that would be typical CGI applications. These are
sometimes referred to as FMV (
Full
motion video).
CGI is used for visual effects because computer generated effects
are more controllable than other more physically based processes,
such as constructing
miniatures for
effects shots or hiring
extras for
crowd scenes, and because it allows the creation of images that
would not be feasible using any other technology. It can also allow
a single graphic artist to produce such content without the use of
actors, expensive set pieces, or props.
3D computer graphics
software is used to make computer-generated imagery for movies,
etc. Recent availability of CGI software and increased computer
speeds have allowed individual artists and small companies to
produce professional grade films, games, and fine art from their
home computers. This has brought about an Internet subculture with
its own set of global celebrities, clichés, and technical
vocabulary.
Simulators, particularly flight simulators, and simulation
generally, make extensive use of CGI techniques for representing
the Outside World.
History
CGI was
first used in movies in 1973's Westworld, though the first use of 3D
Wireframe imagery was in its sequel, Futureworld (1976), which featured a
computer-generated hand and face created by then University of
Utah
graduate students Edwin
Catmull and Fred Parke. The
third movie to use this technology was
Star Wars (1977) for
the scenes with the wireframe Death Star plans and the targeting
computers in the
X-wings and the
Millennium Falcon. In 1978, graduate
students at the
New York
Institute of Technology Computer Graphics Lab began work on
what would have been the first full-length CGI film,
The Works, and a trailer for it
was shown at
SIGGRAPH 1982, but the film
was never completed.
Star Trek II: The Wrath of
Khan premiered a short CGI sequence called The Genesis
Wave in June 1982. The first two films to make heavy investments in
Solid 3D CGI,
Tron (1982) and
The Last Starfighter
(1984), were commercial failures, causing most directors to
relegate CGI to images that were supposed to look like they were
created by a computer.
It was the 1993 film
Jurassic
Park, however, in which dinosaurs created with CGI were
seamlessly integrated into live action scenes, that revolutionized
the movie industry. It marked Hollywood’s transition from
stop-motion animation and conventional
optical effects to digital techniques. The following year, CGI was
used to create the special effects for
Forrest Gump. The most noteworthy effects
shots were those that featured the digital removal of actor
Gary Sinise's legs. Other effects
included a
napalm strike, the fast-moving
Ping-Pong balls, and the digital
insertion of
Tom Hanks into several scenes
of historical footage.
2D CGI increasingly appeared in
traditionally animated films, where it
supplemented the use of hand-illustrated cels. Its uses ranged from
digital
tweening motion between frames, to
eye-catching quasi-3D effects, such as the ballroom scene in
Beauty and the
Beast.
In 1993,
Babylon 5 became the
first television series to use CGI as the primary method for its
visual effects (rather than using hand-built models). It also
marked the first TV use of virtual sets. That same year,
Insektors became the first
full-length completely computer animated TV series. Soon after, in
1994, the hit Canadian CGI show
ReBoot aired.
In 1995, the first fully computer-generated feature film,
Disney-
Pixar's
Toy Story, was a resounding commercial
success.
Additional digital animation studios such as
Blue Sky Studios (20th Century Fox), DNA Productions (Paramount Pictures and Warner Bros.), Omation Studios (Paramount Pictures), Sony Pictures Animation (Columbia Pictures), Vanguard Animation (Walt Disney Pictures, Lions Gate Entertainment and
20th Century Fox), Big Idea Productions (Universal Pictures and FHE Pictures), Animal
Logic (Warner Bros.) and Pacific Data Images (Dreamworks SKG
) went into production, and existing animation
companies, such as The Walt Disney Company, began to make a
transition from traditional animation to CGI.
Between 1995 and 2005 the average effects
budget for a wide-release
feature film skyrocketed from $5 million to $40
million. According to one studio executive, , more than half of
feature films have significant effects. However, CGI has made up
for the expenditures by grossing over 20% more than their real-life
counterparts.
In the early 2000s, computer-generated imagery became the dominant
form of special effects. The technology progressed to the point
that it became possible to include virtual stunt doubles.
Camera tracking software was refined to allow
increasingly complex visual effects developments that were
previously impossible. Computer-generated extras also became used
extensively in crowd scenes with advanced
flocking and crowd simulation software.
The
timeline of
CGI in film and television shows a detailed list of pioneering
uses of computer-generated imagery in film and television.
CGI for films is usually rendered at about 1.4–6
megapixels.
Toy Story, for example, was
rendered at 1536 × 922 (1.42MP). The time to render one
frame is typically around 2–3 hours, with ten times that for the
most complex scenes. This time hasn't changed much in the last
decade, as image quality has progressed at the same rate as
improvements in hardware, since with faster machines, more and more
complexity becomes feasible. Exponential increases in
GPUs processing power, as well as
massive increases in parallel CPU power, storage and memory speed
and size have greatly increased CGI's potential.
In 2001,
Square Pictures created the
CGI film
Final
Fantasy: The Spirits Within, which made headlines for
attempting to create photo-realistic human actors. The film was not
a box-office success. Some commentators have suggested this may be
partly because the lead CGI characters had facial features which
fell into the
uncanny valley. Square
Pictures produced only two more films using a similar visual style
Final Flight of the
Osiris, a short film which served as a prologue to
The Matrix Reloaded and
Final Fantasy
VII: Advent Children, based on their extremely popular
video game series.
Another production which uses CGI almost entirely is
Code Lyoko, a youth television show
regarding a virtual world called Lyoko, its gateway to the real
world, and the computer program planning to take over the world,
Xana . The show is partially 2D animated, and
partially CGI animated. 2D animation describes the real world,
where CGI rendering describes the virtual world of
Lyoko, after the show's main characters have been
scanned and converted into
it.
Developments in CGI technologies are reported each year at
SIGGRAPH, an annual conference on computer graphics
and interactive techniques, attended each year by tens of thousands
of computer professionals.
Developers of computer games and 3D video cards strive to achieve
the same visual quality on personal computers in real-time as is
possible for CGI films and animation. With the rapid advancement of
real-time rendering quality, artists began to use
game engines to render non-interactive movies.
This art form is called
machinima.
Creating characters and objects on a computer
3D computer animation combines 3D models of objects and programmed
movement. Models are constructed out of geometrical vertices,
faces, and edges in a 3D coordinate system. Objects are sculpted
much like real clay or plaster, working from general forms to
specific details with various sculpting tools. A bone/joint system
is set up to deform the 3D mesh (e.g., to make a humanoid model
walk). In a process called rigging, the virtual marionette is given
various controllers and handles for controlling movement. Animation
data can be created using
motion
capture, or
keyframing by a human
animator, or a combination of the two.
3D models rigged for animation may contain hundreds of control
points - for example, the character "Woody" in
Pixar's movie
Toy
Story, uses 700 specialized animation controllers.
Rhythm and Hues Studios
labored for two years to create
Aslan in the
movie
The
Chronicles of Narnia: The Lion, the Witch and the Wardrobe
which had about 1851 controllers, 742 in just the face alone. In
the 2004 film
The Day After
Tomorrow, designers had to design forces of extreme
weather with the help of video references and accurate
meteorological facts.
For the
2005 remake of
King Kong, actor
Andy Serkis was used to help designers
pinpoint the gorilla's prime location in the shots and used his
expressions to model "human" characteristics onto the creature.
Serkis had earlier provided the voice and performance for
Gollum in
Peter
Jackson's
The Lord of the
Rings trilogy.
Communities
There are a multitude of websites designed to help promote and
support CGI artists. Some are managed by software developers and
content providers, but there are standalone sites as well,
including one of the largest communities on the web,
Renderosity. These communities allow for members
to seek advice, post tutorials, provide product reviews or post
examples of their own work.
CGI film studios
CGI visual effects studios
See also
References
External links
that includes all course materials and extensive
supplementary materials (videos, articles, links).
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