Computer animation

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(Redirected from
Computer animated
)
An example of computer animation which is produced from the "motion capture" technique

Computer animation is the process used for digitally generating

moving images, while computer animation only refers to moving images. Modern computer animation usually uses 3D computer graphics
.

Computer animation is the digital successor to

props. To create the illusion of movement, an image is displayed on the computer monitor and repeatedly replaced by a new similar image but advanced slightly in time (usually at a rate of 24, 25, or 30 frames/second). This technique is identical to how the illusion of movement is achieved with television and motion pictures
.

Explanation

To trick the visual system into seeing a smoothly moving object, the pictures should be drawn at around 12 frames per second or faster.[1] (A frame is one complete image.) With rates above 75 to 120 frames per second, no improvement in realism or smoothness is perceivable due to the way the eye and the brain both process images. At rates below 12 frames per second, most people can detect jerkiness associated with the drawing of new images that detracts from the illusion of realistic movement.[2] Conventional hand-drawn cartoon animation often uses 15 frames per second in order to save on the number of drawings needed, but this is usually accepted because of the stylized nature of cartoons. To produce more realistic imagery, computer animation demands higher frame rates.

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

3D computer animation

For 3D animations, objects (models) are built on the computer monitor (modeled) and 3D figures are rigged with a virtual skeleton. Then the limbs, eyes, mouth, clothes, etc. of the figure are moved by the animator on key frames. The differences in appearance between key frames are automatically calculated by the computer in a process known as tweening or morphing. Finally, the animation is rendered.

For 3D animations, all frames must be rendered after the modeling is complete. For pre-recorded presentations, the rendered frames are transferred to a different format or medium, like 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. Adobe Flash, X3D) often use the software on the end user's computer to render in real-time as an alternative to streaming or pre-loaded high bandwidth animations.

Computer-generated animation

To animate means, figuratively, to "give life to". There are two basic methods that animators commonly use to accomplish this.

Computer-generated animation is known as three-dimensional (

gravity rulings. Fundamentally, time scale and quality could be said to be a preferred way to produce animation as they are major aspects enhanced by using computer-generated animation. Another positive aspect of CGA is the fact one can create a flock of creatures to act independently when created as a group. An animal's fur can be programmed to wave in the wind and lie flat when it rains instead of separately programming each strand of hair.[3]

A few examples of computer-generated animation movies are Toy Story, Antz, Ice Age, Happy Feet, Despicable Me, Frozen, and Shrek.

2D computer animation

real-time renderings
.

Computer animation is essentially a digital successor to stop motion techniques, but using 3D models, and traditional animation techniques using frame-by-frame animation of 2D illustrations.

For 2D figure animations, separate objects (illustrations) and separate transparent layers are used with or without that virtual skeleton.

2D sprites and pseudocode

In 2D computer animation, moving objects are often referred to as "sprites." 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.[4] The following pseudocode 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-assisted animation

Computer-assisted animation is usually classed as two-dimensional (2D) animation. Drawings are either hand drawn (pencil to paper) or interactively drawn (on the computer) using different assisting appliances and are positioned into specific software packages. Within the software package, the creator places drawings into different key frames which fundamentally create an outline of the most important movements.[5] The computer then fills in the "in-between frames", a process commonly known as Tweening.[6] Computer-assisted animation employs new technologies to produce content faster than is possible with traditional animation, while still retaining the stylistic elements of traditionally drawn characters or objects.[3]

Examples of films produced using computer-assisted animation are The Little Mermaid, The Rescuers Down Under, Beauty and the Beast, Aladdin, The Lion King, Pocahontas, The Hunchback of Notre Dame, Hercules, Mulan, Tarzan, We're Back! A Dinosaur's Story, Balto, Anastasia, Titan A.E., The Prince of Egypt, The Road to El Dorado, Spirit: Stallion of the Cimarron and Sinbad: Legend of the Seven Seas.

Text-to-video

A text-to-video model is a machine learning model which takes as input a natural language description and produces a video matching that description.[7]

Video prediction on making objects realistic in a stable background is performed by using recurrent neural network for a sequence to sequence model with a connector convolutional neural network encoding and decoding each frame pixel by pixel,[8] creating video using deep learning.[9]

History

Early digital computer animation was developed at Bell Telephone Laboratories in the 1960s by Edward E. Zajac, Frank W. Sinden, Kenneth C. Knowlton, and A. Michael Noll.[10] Other digital animation was also practiced at the Lawrence Livermore National Laboratory.[11]

In 1967, a computer animation named "Hummingbird" was created by Charles Csuri and James Shaffer.[12] In 1968, a computer animation called "Kitty" was created with BESM-4 by Nikolai Konstantinov, depicting a cat moving around.[13] In 1971, a computer animation called "Metadata" was created, showing various shapes.[14]

An early step in the history of computer animation was the sequel to the 1973 film

Fred Parke.[16] This imagery originally appeared in their student film A Computer Animated Hand, which they completed in 1972.[17][18]

Developments in CGI technologies are reported each year at SIGGRAPH,[19] an annual conference on computer graphics and interactive techniques that is attended by thousands of computer professionals each year.[20] 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, which led to the art form Machinima.

Film and television

"Spring", a 3D animated short film made using Blender

CGI short films have been produced as independent animation since 1976.[21] Early examples of feature films incorporating CGI animation include the live-action films Star Trek II: The Wrath of Khan and Tron (both 1982),[22] and the Japanese anime film Golgo 13: The Professional (1983).[23] VeggieTales is the first American fully 3D computer-animated series sold directly (made in 1993); its success inspired other animation series, such as ReBoot (1994) and Transformers: Beast Wars (1996) to adopt a fully computer-generated style.

The first full length computer-animated television series was

anthropomorphic toys and their owners, this groundbreaking film was also the first of many fully computer-animated movies.[27]

The popularity of computer animation (especially in the field of special effects) skyrocketed during the modern era of U.S. animation.[29] Films like Avatar (2009) and The Jungle Book (2016) use CGI for the majority of the movie runtime, but still incorporate human actors into the mix.[30] Computer animation in this era has achieved photorealism, to the point that computer-animated films such as The Lion King (2019) are able to be marketed as if they were live-action.[31][32]

Animation methods

3D game character animated using skeletal animation
keyframed
over time to create motion.

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

facial animation exist).[34] The character "Woody" in Toy Story
, for example, uses 712 Avars (212 in the face alone). The computer does not usually render the skeletal model directly (it is invisible), but it does use the skeletal model to compute the exact position and orientation of that certain 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.

keyframing. Keyframing puts control in the hands of the animator and has roots in hand-drawn traditional animation.[36]

In contrast, a newer method called motion capture makes use of live action footage.[37] When computer animation is driven by motion capture, a real performer acts out the scene as if they were the character to be animated.[38] Their motion is recorded to a computer using video cameras and markers and that performance is then applied to the animated character.[39]

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.

Davy Jones
. Even though Nighy does not appear in the movie himself, 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 throughout the conventional costuming.

Modeling

3D computer animation combines 3D models of objects and programmed or hand "keyframed" movement. These models are constructed out of geometrical vertices, faces, and edges in a 3D coordinate system. Objects are

keyframing by a human animator, or a combination of the two.[43]

3D models rigged for animation may contain thousands of control points — for example, "Woody" from 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 1,851 controllers (742 in 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 J. R. R. Tolkien's The Lord of the Rings trilogy.

Equipment

A ray-traced 3-D model of a jack inside a cube, and the jack alone below

Computer animation can be created with a computer and an animation software. Some impressive animation can be achieved even with basic programs; however, the rendering can require much time on an ordinary home computer.

performance capture, bluescreens, film editing software, props, and other tools used for movie animation. Programs like Blender allow for people who can not afford expensive animation and rendering software to be able to work in a similar manner to those who use the commercial grade equipment.[47]

Facial animation

The realistic modeling of human facial features is both one of the most challenging and sought after elements in computer-generated imagery. Computer facial animation is a highly complex field where models typically include a very large number of animation variables.[48] Historically speaking, the first 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.[49]

The Facial Action Coding System (with 46 "action units", "lip bite" or "squint"), which had been developed in 1976, became a popular basis for many systems.[50] As early as 2001, MPEG-4 included 68 Face Animation Parameters (FAPs) for lips, jaws, etc., and the field has made significant progress since then and the use of facial microexpression has increased.[50][51]

In some cases, an affective space, the PAD emotional state model, can be used to assign specific emotions to the faces of avatars.[52] In this approach, the PAD model is used as a high level emotional space and the lower level space is the 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.[53]

Realism

Joy & Heron – a typical example of realistic animation

Realism in computer animation can mean making each frame look

photorealistic rendering.[55]

One trend in computer animation has been the effort to create human characters that look and move with the highest degree of realism. A possible outcome when attempting to make pleasing, realistic human characters is the uncanny valley, the concept where the human audience (up to a point) tends to have an increasingly negative, emotional response as a human replica looks and acts more and more human. Films that have attempted photorealistic human characters, such as The Polar Express,[56][57][58] Beowulf,[59] and A Christmas Carol[60][61] have been criticized as "disconcerting" and "creepy".

The goal of computer animation is not always to emulate live action as closely as possible, so many animated films instead feature characters who are

basic principles of animation, like squash and stretch, call for movement that is not strictly realistic, and such principles still see widespread application in computer animation.[63]

Web animations

The popularity of

PowToon and Vyond attempt to bridge the gap by giving amateurs access to professional animations as clip art
.

The oldest (most backward compatible) web-based animations are in the animated

never fully supported the Flash plugin.

By this time,

video compression technology. However, compatibility was still problematic as some of the video formats such as Apple's QuickTime and Microsoft Silverlight required plugins. YouTube was also relying on the Flash plugin to deliver digital video in the Flash Video
format.

The latest alternatives are

SmartSketch. YouTube offers an HTML5 alternative for digital video. APNG
(Animated PNG) offered a raster graphic alternative to animated GIF files that enables multi-level transparency not available in GIFs.

Detailed examples

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

Boolean operations
on regular shapes, and has the advantage that animations may be accurately produced at any resolution.

Animation studios

Some notable producers of computer-animated feature films include:

See also

References

Citations

  1. ^ Masson 1999, p. 148.
  2. ^ Parent 2012, pp. 100–101, 255.
  3. ^ a b Roos, Dave (2013). "How Computer Animation Works". HowStuffWorks. Retrieved 2013-02-15.
  4. ^ Masson 1999, p. 123.
  5. ^ Masson 1999, p. 115.
  6. ^ Masson 1999, p. 284.
  7. ^ Artificial Intelligence Index Report 2023 (PDF) (Report). Stanford Institute for Human-Centered Artificial Intelligence. p. 98. Multiple high quality text-to-video models, AI systems that can generate video clips from prompted text, were released in 2022.
  8. ^ "Leading India" (PDF).
  9. ^ Narain, Rohit (2021-12-29). "Smart Video Generation from Text Using Deep Neural Networks". Retrieved 2022-10-12.
  10. ^ Masson 1999, pp. 390–394.
  11. ^ Sito 2013, pp. 69–75.
  12. ^ "Charles Csuri, Fragmentation Animations, 1967 – 1970: Hummingbird (1967)". YouTube.
  13. ^ ""Kitten" 1968 computer animation". YouTube.
  14. ^ "Metadata 1971". YouTube.
  15. ^ Masson 1999, p. 404.
  16. ^ Masson 1999, pp. 282–288.
  17. ^ Sito 2013, p. 64.
  18. ^ Means 2011.
  19. ^ Sito 2013, pp. 97–98.
  20. ^ Sito 2013, pp. 95–97.
  21. ^ Masson 1999, p. 58.
  22. ^ "The Making of Tron". Video Games Player. Vol. 1, no. 1. Carnegie Publications. September 1982. pp. 50–5.
  23. .
  24. ^ Sito 2013, p. 188.
  25. ^ Masson 1999, p. 430.
  26. ^ Masson 1999, p. 432.
  27. ^ a b Masson 1999, p. 302.
  28. ^ "Our Story", Pixar, 1986–2013. Retrieved on 2013-02-15. "The Pixar Timeline, 1979 to Present". Pixar. Archived from the original on 2015-09-05.
  29. ^ Masson 1999, p. 52.
  30. ^ Thompson, Anne (2010-01-01). "How James Cameron's Innovative New 3D Tech Created Avatar". Popular Mechanics. Retrieved 2019-04-24.
  31. ^ Fleming, Mike Jr. (October 13, 2016). "Disney's Live-Action 'Lion King' Taps Jeff Nathanson As Writer". Deadline Hollywood. Archived from the original on October 15, 2016. Retrieved July 9, 2019.
  32. ^ Rottenberg, Josh (July 19, 2019). "'The Lion King': Is it animated or live-action? It's complicated". Los Angeles Times. Retrieved December 13, 2021.
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  49. ^ Parke & Waters 2008, p. xi.
  50. ^ a b Magnenat Thalmann & Thalmann 2004, p. 122.
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  56. Salon
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  57. ^ Herman, Barbara (2013-10-30). "The 10 Scariest Movies and Why They Creep Us Out". Newsweek. Retrieved 2015-06-08.
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Works cited

External links