Computer animation - AbsoluteAstronomy.com

Computer animation is the process used for generating animated images

Animation

Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...

by using computer graphics

Computer graphics

Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....

. The more general term computer generated imagery encompasses both static scenes and dynamic images, while computer animation only refers to moving images.

Modern computer animation usually uses 3D computer graphics, although 2D computer graphics are still used for stylistic, low bandwidth, and faster real-time renderings. Sometimes the target of the animation is the computer itself, but sometimes the target is another medium, such as film

Film

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...

.

Computer animation is essentially a digital successor to the stop motion

Stop motion

Stop motion is an animation technique to make a physically manipulated object appear to move on its own. The object is moved in small increments between individually photographed frames, creating the illusion of movement when the series of frames is played as a continuous sequence...

techniques used in traditional animation

Traditional animation

Traditional animation, is an animation technique where each frame is drawn by hand...

with 3D models and frame-by-frame animation of 2D illustrations. Computer generated animations are more controllable than other more physically based processes, such as constructing miniatures

Miniature effect

A miniature effect is a special effect created for motion pictures and television programs using scale models. Scale models are often combined with high speed photography or matte shots to make gravitational and other effects appear convicing to the viewer...

for effects shots or hiring extras

Extra (actor)

A background actor or extra is a performer in a film, television show, stage, musical, opera or ballet production, who appears in a nonspeaking, nonsinging or nondancing capacity, usually in the background...

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

Theatrical property

A theatrical property, commonly referred to as a prop, is an object used on stage by actors to further the plot or story line of a theatrical production. Smaller props are referred to as "hand props". Larger props may also be set decoration, such as a chair or table. The difference between a set...

.

To create the illusion of movement, an image is displayed on the computer screen

Computer display

A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

and repeatedly replaced by a new image that is similar to it, but advanced slightly in the time domain (usually at a rate of 24 or 30 frames/second). This technique is identical to how the illusion of movement is achieved with television

Television

Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

and motion pictures

Film

.

For 3D animations, objects (models) are built on the computer monitor (modeled) and 3D figures are rigged with a virtual skeleton. For 2D figure animations, separate objects (illustrations) and separate transparent layers are used, with or without a virtual skeleton. Then the limbs, eyes, mouth, clothes, etc. of the figure are moved by the animator on key frame

Key frame

A key frame in animation and filmmaking is a drawing that defines the starting and ending points of any smooth transition. They are called "frames" because their position in time is measured in frames on a strip of film...

s. The differences in appearance between key frames are automatically calculated by the computer in a process known as tweening or morphing

Morphing

Morphing is a special effect in motion pictures and animations that changes one image into another through a seamless transition. Most often it is used to depict one person turning into another through technological means or as part of a fantasy or surreal sequence. Traditionally such a depiction...

. Finally, the animation is rendered

Rendering (computer graphics)

Rendering is the process of generating an image from a model , by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene...

.

For 3D animations, all frames must be rendered after modeling is complete. For 2D vector animations, the rendering process is the key frame illustration process, while tweened frames are rendered as needed. For pre-recorded presentations, the rendered frames are transferred to a different format or medium such as film or digital video. The frames may also be rendered in real time as they are presented to the end-user audience. Low bandwidth animations transmitted via the internet (e.g. 2D Flash

Adobe Flash

Adobe Flash is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements, games and flash animations for broadcast...

, X3D

X3D

X3D is the ISO standard XML-based file format for representing 3D computer graphics, the successor to the Virtual Reality Modeling Language . X3D features extensions to VRML X3D is the ISO standard XML-based file format for representing 3D computer graphics, the successor to the Virtual Reality...

) often use software on the end-users computer to render in real time as an alternative to streaming

Streaming media

Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a streaming provider.The term "presented" is used in this article in a general sense that includes audio or video playback. The name refers to the delivery method of the medium rather...

or pre-loaded high bandwidth animations.

A simple example

The screen is blanked to a background color, such as black. Then, a goat is drawn on the right of the screen. Next, the screen is blanked, but the goat is re-drawn or duplicated slightly to the left of its original position. This process is repeated, each time moving the goat a bit to the left. If this process is repeated fast enough, the goat will appear to move smoothly to the left. This basic procedure is used for all moving pictures in films and television.

The moving goat is an example of shifting the location of an object. More complex transformations of object properties such as size, shape, lighting effects often require calculations and computer rendering instead of simple re-drawing or duplication.

Explanation

To trick the eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

and brain

Human brain

The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...

into thinking they are seeing a smoothly moving object, the pictures should be drawn at around 12 frames per second

Frame rate

Frame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...

(frame/s) or faster (a frame

Film frame

In filmmaking, video production, animation, and related fields, a film frame or video frame is one of the many still images which compose the complete moving picture...

is one complete image). With rates above 70 frames/s no improvement in realism or smoothness is perceivable due to the way the eye and brain process images. At rates below 12 frame/s most people can detect jerkiness

Jerkiness

Jerkiness, sometimes called strobing, describes the perception of individual still images in a motion picture.Motion pictures are made from still images shown in rapid sequence...

associated with the drawing of new images which detracts from the illusion of realistic movement. Conventional hand-drawn cartoon animation often uses 15 frames/s in order to save on the number of drawings needed, but this is usually accepted because of the stylized nature of cartoons. Because it produces more realistic imagery computer animation demands higher frame rates to reinforce this realism.

Movie film seen in theaters in the United States runs at 24 frames per second, which is sufficient to create the illusion of continuous movement. For high resolution, adapters are used.

History

Some of the earliest animation done using a digital computer was done at Bell Telephone Laboratories in the first half of the 1960s by Edward E. Zajac, Frank W. Sinden, Kenneth C. Knowlton, and A. Michael Noll. Early digital animation was also done at Lawrence Livermore Laboratory.

Another early step in the history of computer animation

History of computer animation

Researchers at Bell Telephone Laboratories in Murray Hill, NJ did some of the earliest computer animation in the early and mid 1960s. In 1963, Dr. Edward E. Zajac created a computer-animated movie showing a satellite orbiting the Earth. Around that time, Dr. Frank W. Sinden created a...

was the 1973 movie Westworld
Westworld
Westworld is a 1973 science fiction-thriller film written and directed by novelist Michael Crichton and produced by Paul Lazarus III. It stars Yul Brynner as a lifelike robot in a futuristic Western-themed amusement park, and Richard Benjamin and James Brolin as guests of the park.Westworld was the...

, a science-fiction film about a society in which robots live and work among humans, though the first use of 3D Wireframe imagery was in its sequel, Futureworld
Futureworld
Futureworld is a 1976 sequel to the 1973 science fiction film Westworld. It was written by George Schenk and Mayo Simon, and directed by Richard T. Heffron. The cast included Peter Fonda, Blythe Danner, and Arthur Hill. There is also a cameo appearance by Yul Brynner in a dream sequence...

(1976), which featured a computer-generated hand and face created by then University of Utah

University of Utah

The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

graduate students Edwin Catmull

Edwin Catmull

Dr. Edwin Earl Catmull, Ph.D. is a computer scientist and current president of Walt Disney Animation Studios and Pixar Animation Studios. As a computer scientist, Catmull has contributed to many important developments in computer graphics....

and Fred Parke

Fred Parke

Frederic Ira Parke graduated from the University of Utah with a BS degree in physics in 1965. He was then a graduate student of the University of Utah College of Engineering where he received his MS and PhD in computer science. Parke was the creator of the first CG physically modeled human face...

.

Developments in CGI technologies are reported each year at SIGGRAPH

SIGGRAPH

SIGGRAPH is the name of the annual conference on computer graphics convened by the ACM SIGGRAPH organization. The first SIGGRAPH conference was in 1974. The conference is attended by tens of thousands of computer professionals...

, 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 engine

Game engine

A game engine is a system designed for the creation and development of video games. There are many game engines that are designed to work on video game consoles and personal computers...

s to render non-interactive movies. This art form is called machinima
Machinima
Machinima is the use of real-time 3D computer graphics rendering engines to create a cinematic production. Most often, video games are used to generate the computer animation...

.

The first feature-length computer animated film was the 1995 movie Toy Story
Toy Story
Toy Story is a 1995 American computer-animated film released by Walt Disney Pictures. It is Pixar's first feature film as well as the first ever feature film to be made entirely with CGI. The film was directed by John Lasseter and featuring the voices of Tom Hanks and Tim Allen...

by Pixar

Pixar

Pixar Animation Studios, pronounced , is an American computer animation film studio based in Emeryville, California. The studio has earned 26 Academy Awards, seven Golden Globes, and three Grammy Awards, among many other awards and acknowledgments. Its films have made over $6.3 billion worldwide...

. It followed an adventure centered around some toys and their owners. The groundbreaking film was the first of many fully computer animated films.

Computer animation helped make blockbuster films such as Toy Story 3
Toy Story 3
Toy Story 3 is a 2010 American 3D computer-animated comedy-adventure film, and the third installment in the Toy Story series. It was produced by Pixar and released by Walt Disney Pictures. It was directed by Lee Unkrich. The film was released worldwide from June through October in Disney Digital...

(2010), Avatar (2009), and Shrek 2
Shrek 2
Shrek 2 is a 2004 American computer-animated fantasy comedy film, produced by DreamWorks Animation and directed by Andrew Adamson, Kelly Asbury and Conrad Vernon. It is the second installment in the Shrek film series and the sequel to 2001's Shrek...

(2004).

Methods of animating virtual characters

In most 3D computer animation systems, an animator creates a simplified representation of a character's anatomy, analogous to a skeleton

Skeleton

The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...

or stick figure

Stick figure

A stick figure is a very simple type of drawing made of lines and dots, often of the human form or other animals. In a stick figure, the head is represented by a circle, sometimes embellished with details such as eyes, mouth or crudely scratched-out hair. The arms, legs and torso are all...

. The position of each segment of the skeletal model is defined by animation variables, or Avars

Avar (animation variable)

An avar or animation variable is a variable controlling the position of part of an animated object, such as a character. The character "Woody" in Pixar's movie Toy Story uses 712 avars . Successive sets of avars control all movement of the character from frame to frame...

.
In human and animal characters, many parts of the skeletal model correspond to actual bones, but skeletal animation

Skeletal animation

Skeletal animation is a technique in computer animation in which a character is represented in two parts: a surface representation used to draw the character and a hierarchical set of interconnected bones used to animate the mesh...

is also used to animate other things, such as facial features (though other methods for facial animation exist). The character "Woody" in Toy Story
Toy Story
Toy Story is a 1995 American computer-animated film released by Walt Disney Pictures. It is Pixar's first feature film as well as the first ever feature film to be made entirely with CGI. The film was directed by John Lasseter and featuring the voices of Tom Hanks and Tim Allen...

, for example, uses 700 Avars, including 100 Avars in the face. The computer does not usually render

Rendering (computer graphics)

the skeletal model directly (it is invisible), but uses the skeletal model to compute the exact position and orientation of the character, which is eventually rendered into an image. Thus by changing the values of Avars over time, the animator creates motion by making the character move from frame to frame.

There are several methods for generating the Avar values to obtain realistic motion. Traditionally, animators manipulate the Avars directly. Rather than set Avars for every frame, they usually set Avars at strategic points (frames) in time and let the computer interpolate or 'tween

Tweening

Inbetweening or tweening is the process of generating intermediate frames between two images to give the appearance that the first image evolves smoothly into the second image. Inbetweens are the drawings between the key frames which help to create the illusion of motion...

' between them, a process called keyframing. Keyframing puts control in the hands of the animator, and has roots in hand-drawn traditional animation

Traditional animation

Traditional animation, is an animation technique where each frame is drawn by hand...

.

In contrast, a newer method called motion capture

Motion capture

Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating that movement on to a digital model. It is used in military, entertainment, sports, and medical applications, and for validation of computer vision and robotics...

makes use of live action

Live action

In filmmaking, video production, and other media, the term live action refers to cinematography, videography not produced using animation...

. When computer animation is driven by motion capture, a real performer acts out the scene as if they were the character to be animated. His or her motion is recorded to a computer using video camera

Video camera

A video camera is a camera used for electronic motion picture acquisition, initially developed by the television industry but now common in other applications as well. The earliest video cameras were those of John Logie Baird, based on the electromechanical Nipkow disk and used by the BBC in...

s and markers, and that performance is then applied to the animated character.

Each method has its advantages, and as of 2007, games and films are using either or both of these methods in productions. Keyframe animation can produce motions that would be difficult or impossible to act out, while motion capture can reproduce the subtleties of a particular actor. For example, in the 2006 film Pirates of the Caribbean: Dead Man's Chest

Pirates of the Caribbean: Dead Man's Chest

Pirates of the Caribbean: Dead Man's Chest is a 2006 adventure fantasy film and the second film of the Pirates of the Caribbean series, following Pirates of the Caribbean: The Curse of the Black Pearl . It was directed by Gore Verbinski, written by Ted Elliott and Terry Rossio, and produced by...

, actor Bill Nighy

Bill Nighy

William Francis "Bill" Nighy is an English actor and comedian. He worked in theatre and television before his first cinema role in 1981, and made his name in television with The Men's Room in 1991, in which he played the womanizer Prof...

provided the performance for the character Davy Jones

Davy Jones (Pirates of the Caribbean)

Davy Jones is a fictional character and antagonist in the Pirates of the Caribbean series. Davy Jones is the captain of the Flying Dutchman , roaming the seas in search of souls to serve upon his vessel for a century...

. Even though Nighy himself doesn't appear in the film, the movie benefited from his performance by recording the nuances of his body language, posture, facial expressions, etc. Thus motion capture is appropriate in situations where believable, realistic behavior and action is required, but the types of characters required exceed what can be done through conventional costuming.

Creating characters and objects on a computer

3D computer animation combines 3D models of objects and programmed or hand "keyframed" 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 animation system is set up to deform the CGI model (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

Motion capture

, or keyframing by a human animator, or a combination of the two.

3D models rigged for animation may contain thousands of control points - for example, the character "Woody" in Pixar

Pixar

's movie Toy Story
Toy Story
Toy Story is a 1995 American computer-animated film released by Walt Disney Pictures. It is Pixar's first feature film as well as the first ever feature film to be made entirely with CGI. The film was directed by John Lasseter and featuring the voices of Tom Hanks and Tim Allen...

, uses 700 specialized animation controllers. Rhythm and Hues Studios

Rhythm and Hues Studios

Rhythm & Hues Studios is a visual effects studio serving the major film studios. It is known for its computer-generated 3D character animation. Recognized as one of the top facilities of its kind in the world, Rhythm & Hues has contributed to more than 150 feature films...

labored for two years to create Aslan

Aslan

Aslan, the "Great Lion," is the central character in The Chronicles of Narnia, a series of seven fantasy novels for children written by C. S. Lewis. He is the eponymous lion of The Lion, the Witch and the Wardrobe, and his role in Narnia is developed throughout the remaining books...

in the movie The Chronicles of Narnia: The Lion, the Witch and the Wardrobe
The Chronicles of Narnia: The Lion, the Witch and the Wardrobe
The Chronicles of Narnia: The Lion, the Witch and the Wardrobe is a 2005 epic fantasy adventure film directed by Andrew Adamson and based on The Lion, the Witch and the Wardrobe, the first published and second chronological novel in C. S. Lewis's children's epic fantasy series, The Chronicles of...

which had about 1851 controllers, 742 in just the face alone. In the 2004 film The Day After Tomorrow
The Day After Tomorrow
The Day After Tomorrow is a 2004 American science-fiction disaster film that depicts the catastrophic effects of global warming in a series of extreme weather events that usher in global cooling which leads to a new ice age. The film did well at the box office, grossing $542,771,772 internationally...

, designers had to design forces of extreme weather with the help of video references and accurate meteorological facts. For the 2005 remake

King Kong (2005 film)

King Kong is a 2005 fantasy adventure film directed by Peter Jackson. It is a remake of the 1933 film of the same name and stars Naomi Watts, Jack Black and Adrien Brody. Andy Serkis, through performance capture, portrays Kong....

of King Kong
King Kong (1933 film)
King Kong is a Pre-Code 1933 fantasy monster adventure film co-directed by Merian C. Cooper and Ernest B. Schoedsack, and written by Ruth Rose and James Ashmore Creelman after a story by Cooper and Edgar Wallace. The film tells of a gigantic island-dwelling apeman creature called Kong who dies in...

, actor Andy Serkis

Andy Serkis

Andrew Clement G. "Andy" Serkis is an English actor, director and author. He is popularly known for playing Gollum in The Lord of the Rings film trilogy, for which he earned several award nominations, including the Saturn Award for Best Supporting Actor for his performance in The Two Towers...

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

Gollum

Gollum is a fictional character from J. R. R. Tolkien's legendarium. He was introduced in the author's fantasy novel The Hobbit, and became an important supporting character in its sequel, The Lord of the Rings....

in J. R. R. Tolkien

J. R. R. Tolkien

John Ronald Reuel Tolkien, CBE was an English writer, poet, philologist, and university professor, best known as the author of the classic high fantasy works The Hobbit, The Lord of the Rings, and The Silmarillion.Tolkien was Rawlinson and Bosworth Professor of Anglo-Saxon at Pembroke College,...

's The Lord of the Rings
The Lord of the Rings
The Lord of the Rings is a high fantasy epic written by English philologist and University of Oxford professor J. R. R. Tolkien. The story began as a sequel to Tolkien's earlier, less complex children's fantasy novel The Hobbit , but eventually developed into a much larger work. It was written in...

trilogy.

Computer animation development equipment

Computer animation can be created with a computer and animation software. Some impressive animation can be achieved even with basic programs; however, the render

Rendering (computer graphics)

ing can take a lot of time on an ordinary home computer. Because of this, video game animators tend to use low resolution, low polygon count renders, such that the graphics can be rendered in real time on a home computer. Photorealistic animation would be impractical in this context.

Professional animators of movies, television, and video sequences on computer games make photorealistic animation with high detail. This level of quality for movie animation would take tens to hundreds of years to create on a home computer. Many powerful workstation

Workstation

A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...

computers are used instead. Graphics workstation computers use two to four processors, and thus are a lot more powerful than a home computer, and are specialized for render

Rendering (computer graphics)

ing. A large number of workstations (known as a render farm

Render farm

A render farm is a computer cluster built to render computer-generated imagery , typically for film and television visual effects, using off-line batch processing. This is different from a render wall, which is a networked, tiled display used for real-time rendering...

) are networked together to effectively act as a giant computer. The result is a computer-animated movie that can be completed in about one to five years (this process is not comprised solely of rendering, however). A workstation typically costs $2,000 to $16,000, with the more expensive stations being able to render much faster, due to the more technologically advanced hardware that they contain. Professionals also use digital movie camera

Movie camera

The movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film which was very popular for private use in the last century until its successor, the video camera, replaced it...

s, motion capture

Motion capture

or performance capture, bluescreens, film editing software, prop

Theatrical property

s, and other tools for movie animation.

Modeling human faces

The modeling of human facial features is both one of the most challenging and sought after elements in computer-generated imagery. Computer facial animation

Computer facial animation

Computer facial animation is primarily an area of computer graphics that encapsulates models and techniques for generating and animating images of the human head and face. Due to its subject and output type, it is also related to many other scientific and artistic fields from psychology to...

is a highly complex field where models typically include a very large number of animation variables

Avar (animation variable)

. Historically speaking, the first SIGGRAPH

SIGGRAPH

tutorials on State of the art in Facial Animation in 1989 and 1990 proved to be a turning point in the field by bringing together and consolidating multiple research elements, and sparked interest among a number of researchers.

The Facial Action Coding System

Facial Action Coding System

Facial Action Coding System is a system to taxonomize human facial expressions, originally developed by Paul Ekman and Wallace V. Friesen in 1978...

(with 46 action units such as "lip bite" or "squint") which had been developed in 1976 became a popular basis for many systems. As early as 2001 MPEG-4

MPEG-4

MPEG-4 is a method of defining compression of audio and visual digital data. It was introduced in late 1998 and designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group under the formal standard ISO/IEC...

included 68 facial animation parameters for lips, jaws, etc., and the field has made significant progress since then and the use of facial microexpression

Microexpression

A microexpression is a brief, involuntary facial expression shown on the face of humans according to emotions experienced. They usually occur in high-stakes situations, where people have something to lose or gain. Unlike regular facial expressions, it is difficult to fake microexpressions...

has increased.

In some cases, an affective space

Affect measures

Organizational psychology scholars studying emotion typically use self-report responses to verbal questions to assess participants' current feeling or basic predisposition...

such as the PAD emotional state model

PAD emotional state model

The PAD emotional state model is a psychological model developed by Albert Mehrabian and James A. Russell to describe and measure emotional states. PAD uses three numerical dimensions to represent all emotions....

can be used to assign specific emotions to the faces of avatars

Avatar (computing)

In computing, an avatar is the graphical representation of the user or the user's alter ego or character. It may take either a three-dimensional form, as in games or virtual worlds, or a two-dimensional form as an icon in Internet forums and other online communities. It can also refer to a text...

. In this approach the PAD model is used as a high level emotional space, and the lower level space is the MPEG-4

MPEG-4

Facial Animation Parameters (FAP). A mid-level Partial Expression Parameters (PEP) space is then used to in a two level structure: the PAD-PEP mapping and the PEP-FAP translation model.

The future

One open challenge in computer animation is a photorealistic animation of humans. Currently, most computer-animated movies show animal characters (A Bug's Life
A Bug's Life
A Bug's Life is a 1998 American computer animated adventure comedy film produced by Pixar and released by Walt Disney Pictures in the United States on November 25, 1998. A Bug's Life was the second Disney·Pixar feature film after Toy Story, and the third American computer-animated film after Toy...

, Finding Nemo
Finding Nemo
Finding Nemo is a 2003 American comi-drama animated film written by Andrew Stanton, directed by Andrew Stanton and Lee Unkrich and produced by Pixar. It tells the story of the overly protective clownfish Marlin who, along with a regal tang called Dory , searches for his abducted son Nemo...

, Ratatouille
Ratatouille (film)
Ratatouille is a 2007 American computer-animated comedy film produced by Pixar Animation Studios and distributed by Walt Disney Pictures. It is the eighth film produced by Pixar, and was directed by Brad Bird, who took over from Jan Pinkava in 2005...

, Ice Age
Ice Age (film)
Ice Age is a 2002 American computer-animated film created by Blue Sky Studios and released by 20th Century Fox. It was directed by Carlos Saldanha and Chris Wedge from a story by Michael J. Wilson. The story follows three Paleolithical mammals attempting to return a lost human baby to its parents...

, Over the Hedge
Over the Hedge
Over the Hedge is a syndicated comic strip written and drawn by Michael Fry and T. Lewis. It tells the story of a raccoon, turtle, a squirrel, and their friends who come to terms with their woodlands being taken over by suburbia, trying to survive the increasing flow of humanity and technology...

, Open Season
Open Season (film)
Open Season is a 2006 computer-animated comedy film, written by Steve Bencich and Ron J. Friedman and directed by Jill Culton, Roger Allers, and Anthony Stacchi, and production designed by Michael Humphries...

, Rio
Rio (film)
Rio, often promoted as Rio: The Movie, is a 2011 American 3D computer-animated musical comedy film produced by Blue Sky Studios and directed by Carlos Saldanha. The title refers to the Brazilian city of Rio de Janeiro, in which the film is set. The film features the voices of Jesse Eisenberg, Anne...

), fantasy characters (Monsters Inc., Shrek
Shrek
Shrek is a 2001 American computer-animated fantasy comedy film directed by Andrew Adamson and Vicky Jenson, featuring the voices of Mike Myers, Eddie Murphy, Cameron Diaz, and John Lithgow. Loosely based on William Steig's 1990 fairy tale picture book Shrek!...

, TMNT, Monsters vs. Aliens
Monsters vs. Aliens
Monsters vs. Aliens is a 2009 American computer-animated 3-D science fiction film produced by DreamWorks Animation and distributed by Paramount Pictures...

), anthropomorphic machines (Cars, WALL-E
WALL-E
WALL-E, promoted with an interpunct as WALL•E, is a 2008 American computer-animated science fiction film produced by Pixar Animation Studios and directed by Andrew Stanton. The story follows a robot named WALL-E, who is designed to clean up a waste-covered Earth far in the future...

, Robots) or cartoon-like humans (The Incredibles
The Incredibles
The Incredibles is a 2004 American computer-animated action-comedy superhero film about a family of superheroes who are forced to hide their powers. It was written and directed by Brad Bird, a former director and executive consultant of The Simpsons, and was produced by Pixar and distributed by...

, Despicable Me
Despicable Me
Despicable Me is a 2010 American computer-animated 3D comedy film from Universal Pictures and Illumination Entertainment that was released on July 9, 2010 in the United States. The film features the voices of Steve Carell, Jason Segel, Russell Brand, Julie Andrews, Will Arnett, Kristen Wiig, and...

, Up
Up (2009 film)
Up is a 2009 American computer-animated comedy-adventure film produced by Pixar, distributed by Walt Disney Pictures and presented in Disney Digital 3-D. The film premiered on May 29, 2009 in North America and opened the 2009 Cannes Film Festival, becoming the first animated and 3D film...

). The movie Final Fantasy: The Spirits Within
Final Fantasy: The Spirits Within
Final Fantasy: The Spirits Within is a 2001 Japanese-American computer animated science fiction film directed by Hironobu Sakaguchi, creator of the Final Fantasy series of role-playing video games. It was the first photorealistic computer animated feature film and also holds the record for the most...

is often cited as the first computer-generated movie to attempt to show realistic-looking humans. However, due to the enormous complexity of the human body, human motion, and human biomechanics, realistic simulation of humans remains largely an open problem. Another problem is the distasteful psychological response to viewing nearly perfect animation of humans, known as "the uncanny valley

Uncanny Valley

The uncanny valley is a hypothesis in the field of robotics and 3D computer animation, which holds that when human replicas look and act almost, but not perfectly, like actual human beings, it causes a response of revulsion among human observers...

." It is one of the "holy grails" of computer animation. Eventually, the goal is to create software where the animator can generate a movie sequence showing a photorealistic human character, undergoing physically plausible motion, together with clothes, photorealistic hair, a complicated natural background, and possibly interacting with other simulated human characters. This could be done in a way that the viewer is no longer able to tell if a particular movie sequence is computer-generated, or created using real actors in front of movie cameras. Complete human realism is not likely to happen very soon, but when it does it may have major repercussions for the film industry.

For the moment it looks like three dimensional computer animation can be divided into two main directions; photorealistic and non-photorealistic rendering. Photorealistic computer animation can itself be divided into two subcategories; real photorealism (where performance capture is used in the creation of the virtual human characters) and stylized photorealism. Real photorealism is what Final Fantasy tried to achieve and will in the future most likely have the ability to give us live action fantasy features as The Dark Crystal
The Dark Crystal
The Dark Crystal is a 1982 British-American fantasy film directed by Jim Henson and Frank Oz. Although marketed as a family film, it was notably darker than previous material created by them. The animatronics used in the film were considered groundbreaking. The primary concept artist was the...

without having to use advanced puppetry and animatronics, while Antz
Antz
Antz is a 1998 American computer animated action adventure film produced by DreamWorks Animation. It features the voices of well-known actors such as Woody Allen, Sharon Stone, Jennifer Lopez, Sylvester Stallone, Dan Aykroyd, Anne Bancroft, Gene Hackman, Christopher Walken, and Danny Glover as...

is an example on stylistic photorealism (in the future stylized photorealism will be able to replace traditional stop motion animation as in Corpse Bride
Corpse Bride
Corpse Bride, often promoted as Tim Burton's Corpse Bride, is a 2005 stop-motion-animated fantasy musical film directed by Mike Johnson and Tim Burton. It is set in a fictional Victorian era village in Europe. Johnny Depp led an all-star cast as the voice of Victor, while Helena Bonham Carter ...

, Coraline

Coraline

Coraline is a horror/fantasy novella by British author Neil Gaiman, published in 2002 by Bloomsbury and Harper Collins. It was awarded the 2003 Hugo Award for Best Novella, the 2003 Nebula Award for Best Novella, and the 2002 Bram Stoker Award for Best Work for Young Readers...

, Nightmare Before Christmas). None of these mentioned are perfected as of yet, but the progress continues.

The non-photorealistic/cartoonish direction is more like an extension of traditional animation, an attempt to make the animation look like a three dimensional version of a cartoon, still using and perfecting the main principles of animation articulated by the Nine Old Men, such as squash and stretch.

While a single frame from a photorealistic computer-animated feature will look like a photo if done right, a single frame vector from a cartoonish computer-animated feature will look like a painting (not to be confused with cel shading, which produces an even simpler look).

It should be noted that while video games are nowhere near the artistic capabilities of computer animated films, certain advances have been made towards realistic humans. While films such as Polar Express and Mars Needs Moms have made steps towards realism, the uncanny valley is still present. Some recent games however, most notably L.A. Noire, feature very convincing computer animated human faces and movement.

Detailed examples and pseudocode

In 2D computer animation, moving objects are often referred to as “sprite

Sprite (computer graphics)

In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...

s.” A sprite is an image that has a location associated with it. The location of the sprite is changed slightly, between each displayed frame, to make the sprite appear to move. The following pseudocode

Pseudocode

In computer science and numerical computation, pseudocode is a compact and informal high-level description of the operating principle of a computer program or other algorithm. It uses the structural conventions of a programming language, but is intended for human reading rather than machine reading...

makes a sprite move from left to right:

var int x := 0, y := screenHeight / 2;
while x < screenWidth
drawBackground
drawSpriteAtXY (x, y) // draw on top of the background
x := x + 5 // move to the right

Computer animation uses different techniques to produce animations. Most frequently, sophisticated mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

is used to manipulate complex three dimensional polygon

Polygon

In geometry a polygon is a flat shape consisting of straight lines that are joined to form a closed chain orcircuit.A polygon is traditionally a plane figure that is bounded by a closed path, composed of a finite sequence of straight line segments...

s, apply “texture

Texture mapping

Texture mapping is a method for adding detail, surface texture , or color to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in his Ph.D. thesis of 1974.-Texture mapping:...

s”, lighting and other effects to the polygons and finally rendering

Rendering (computer graphics)

the complete image. A sophisticated graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

may be used to create the animation and arrange its choreography. Another technique called constructive solid geometry

Constructive solid geometry

Constructive solid geometry is a technique used in solid modeling. Constructive solid geometry allows a modeler to create a complex surface or object by using Boolean operators to combine objects...

defines objects by conducting boolean operations on regular shapes, and has the advantage that animations may be accurately produced at any resolution.

Let's step through the rendering of a simple image of a room with flat wood walls with a grey pyramid in the center of the room. The pyramid will have a spotlight shining on it. Each wall, the floor and the ceiling is a simple polygon, in this case, a rectangle. Each corner of the rectangles is defined by three values referred to as X, Y and Z. X is how far left and right the point is. Y is how far up and down the point is, and Z is far in and out of the screen the point is. The wall nearest us would be defined by four points: (in the order x, y, z). Below is a representation of how the wall is defined



(0, 10, 0)                        (10, 10, 0)



(0,0,0)                           (10, 0, 0)

The far wall would be:



(0, 10, 20)                        (10, 10, 20)



(0, 0, 20)                         (10, 0, 20)

The pyramid is made up of five polygons: the rectangular base, and four triangular sides. To draw this image the computer uses math to calculate how to project this image, defined by three dimensional data, onto a two dimensional computer screen.

First we must also define where our view point is, that is, from what vantage point will the scene be drawn. Our view point is inside the room a bit above the floor, directly in front of the pyramid. First the computer will calculate which polygons are visible. The near wall will not be displayed at all, as it is behind our view point. The far side of the pyramid will also not be drawn as it is hidden by the front of the pyramid.

Next each point is perspective projected onto the screen. The portions of the walls ‘furthest’ from the view point will appear to be shorter than the nearer areas due to perspective. To make the walls look like wood, a wood pattern, called a texture, will be drawn on them. To accomplish this, a technique called “texture mapping

Texture mapping

” is often used. A small drawing of wood that can be repeatedly drawn in a matching tiled pattern (like desktop wallpaper) is stretched and drawn onto the walls' final shape. The pyramid is solid grey so its surfaces can just be rendered as grey. But we also have a spotlight. Where its light falls we lighten colors, where objects blocks the light we darken colors.

Next we render the complete scene on the computer screen. If the numbers describing the position of the pyramid were changed and this process repeated, the pyramid would appear to move.

Movies

CGI short films have been produced as independent animation

Independent animation

Independent animation is a term used to describe animated short cartoons and feature films produced outside the professional Hollywood animation industry.- Early independent animation :The history of animation is as old as the film industry itself...

since 1976, though the popularity of computer animation (especially in the field of special effect

Special effect

The illusions used in the film, television, theatre, or entertainment industries to simulate the imagined events in a story are traditionally called special effects ....

s) skyrocketed during the modern era of U.S. animation. The first completely computer-generated television series was ReBoot
ReBoot
ReBoot is a Canadian CGI-animated action-adventure cartoon series that originally aired from 1994 to 2001. It was produced by Vancouver-based production company Mainframe Entertainment, Alliance Communications, BLT Productions and created by Gavin Blair, Ian Pearson, Phil Mitchell and John Grace,...

, in 1994, and the first completely computer-generated animated movie was Toy Story
Toy Story
Toy Story is a 1995 American computer-animated film released by Walt Disney Pictures. It is Pixar's first feature film as well as the first ever feature film to be made entirely with CGI. The film was directed by John Lasseter and featuring the voices of Tom Hanks and Tim Allen...

(1995). See List of computer-animated films for more.

Amateur animation

The popularity of website

Website

A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

s which allows members to upload their own movies for others to view has created a growing community of amateur

Amateur

An amateur is generally considered a person attached to a particular pursuit, study, or science, without pay and often without formal training....

computer animators. With utilities and programs often included free with modern operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, many users can make their own animated movies and shorts. Several free and open source

Free and open source software

Free and open-source software or free/libre/open-source software is software that is liberally licensed to grant users the right to use, study, change, and improve its design through the availability of its source code...

animation software applications exist as well. A popular amateur approach to animation is via the animated GIF

GIF

The Graphics Interchange Format is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability....

format, which can be uploaded and seen on the web easily.

External links

Animation lessons from Amazing-kids.org
CG101: A Computer Graphics Industry Reference, Terrence Masson
Terrence Masson
Terrence Masson is an independent Producer and Director of the Creative Industries program at Northeastern University in Boston, MA. He was both the ACM SIGGRAPH 2006 Computer Animation Festival Chair and 2010 Conference Chair...

. ISBN 0-7357-0046-X (Histories of early computer graphics production)

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

A simple example

Explanation

History

Methods of animating virtual characters

Creating characters and objects on a computer

Computer animation development equipment

Modeling human faces

The future

Detailed examples and pseudocode

Movies

Amateur animation

See also

Animated images in Wikipedia

External links