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{{Short description|Application of computer graphics to create or contribute to images}}
{{Distinguish|AI-generated imagery}}
[[File:Morphogenic digital art exhibition by Andy Lomas at Watermans Arts Centre, London.jpg|thumb|''[[Morphogenetic]] Creations'' computer-generated [[digital art]] exhibition by [[Andy Lomas]] at [[Watermans Arts Centre]], west [[London]], in 2016]]
{{3D computer graphics}}
'''Computer-generated imagery''' ('''CGI''') is a specific-technology or application of [[computer graphics]] for creating or improving images in [[Digital art|art]], [[Publishing|printed media]], [[Training simulation|simulators]], videos and video games. These images are either static (i.e. [[still image]]s) or dynamic (i.e. moving images). CGI both refers to 2D computer graphics and (more frequently) 3D computer graphics with the purpose of designing characters, [[virtual world]]s, or scenes and [[Visual effects|special effects]] (in [[film]]s, television programs, commercials, etc.). The application of CGI for creating/improving [[animation]]s is called ''[[computer animation]]'' (or ''CGI animation'').
==History==
The first feature film to use CGI as well as the composition of live-action film with CGI was ''[[Vertigo (film)|Vertigo]]'',<ref>{{Cite web |last=Ozturk |first=Selen |date=March 15, 2023 |title=Vicious Circle: John Whitney and the Military Origins of Early CGI |url=https://brightlightsfilm.com/vicious-circle-john-whitney-and-the-military-origins-of-early-cgi/#:~:text=Alfred%20Hitchcock's%20Vertigo%20(1958)%20was,film%20to%20use%20computer%20animation. |access-date=May 11, 2023 |website=Bright Lights Film Journal}}</ref> which used abstract computer graphics by [[John Whitney (animator)|John Whitney]] in the opening credits of the film. The first feature film to make use of CGI with live action in the storyline of the film was the 1973 film ''[[Westworld (film)|Westworld]]''.<ref name="insider">{{cite web|url=https://www.insider.com/most-groundbreaking-cgi-movies-ever-created-2020-1|title = 14 groundbreaking movies that took special effects to new levels|website = [[Insider.com]]}}</ref> The first feature film to present a fully CGI character was the 1985 film ''[[Young Sherlock Holmes]]'', showcasing a fully animated stained glass knight character.<ref>{{Cite web |title=First film character computer-generated |url=https://www.guinnessworldrecords.com/world-records/first-film-character-computer-generated |website=[[Guinness World Records]]}}</ref> Other early films that incorporated CGI include ''[[Demon Seed]]'' (1977), ''[[Star Wars (film)|Star Wars]]'' (1977),<ref name="insider"/> ''[[Tron]]'' (1982), ''[[Star Trek II: The Wrath of Khan]]'' (1982),<ref name="insider"/> ''[[Golgo 13: The Professional]]'' (1983),<ref name=":0">{{Cite news|last=Halverson|first=Dave|date=December 2005|title=Anime Reviews: The Professional Golgo 13|page=92|work=Play|issue=48|___location=United States of America}}</ref> ''[[The Last Starfighter]]'' (1984),<ref>{{Cite web |url=https://www.syfy.com/syfywire/the-last-starfighter-sequel-garry-whitta-sizzle-reel |title=Last Starfighter sequel is super close to happening, says Gary Whitta |access-date=2021-08-29 |archive-date=2021-08-29 |archive-url=https://web.archive.org/web/20210829102504/https://www.syfy.com/syfywire/the-last-starfighter-sequel-garry-whitta-sizzle-reel |url-status=dead }}</ref>'' [[The Abyss]]'' (1989), ''[[Terminator 2: Judgment Day|Terminator 2: Judgement Day]]'' (1991), and ''[[Jurassic Park (film)|Jurassic Park]]'' (1993). The first [[music video]] to use CGI was [[Will Powers]]' "Adventures in Success" (1983).<ref>{{cite book |page=134 |last1=Jankel |first1=A. |last2=Morton |first2=R. |title=Creative Computer Graphics |date=Nov 15, 1984 |publisher=Cambridge University Press |isbn=0-521-26251-8}}</ref> In 1995, [[Pixar]]’s ''[[Toy Story]]'' became the first fully CGI feature film, marking a historic milestone for both animation and film-making.<ref>{{Cite web |date=2016-05-23 |title=Toy Story {{!}} Oscars.org {{!}} Academy of Motion Picture Arts and Sciences |url=https://www.oscars.org/collection-highlights/toy-story |access-date=2025-04-24 |website=www.oscars.org |language=en}}</ref>
Prior to CGI being prevalent in film, virtual reality, personal computing and gaming, one of the early practical applications of CGI was for aviation and military training, namely the [[flight simulator]]. Visual systems developed in flight simulators were also an important precursor to three dimensional computer graphics and Computer Generated Imagery (CGI) systems today. Namely because the object of flight simulation was to reproduce on the ground the behavior of an aircraft in flight. Much of this reproduction had to do with believable visual synthesis that mimicked reality.<ref>{{cite book |last1=Rolfe, J. M. and Staples, K.J. |title=Flight Simulation (Cambridge Aerospace Series, Series Number 1) |date=May 27, 1988 |publisher=Cambridge University Press |___location=New York |isbn=978-0521357517}}</ref> The Link Digital Image Generator (DIG) by the Singer Company (Singer-Link), was considered one of the world's first generation CGI systems.<ref>{{cite web |last1=Carlson |first1=Wayne |title=Computer Graphics and Animation: A Retrospective Overview |date=20 June 2017 |url=https://ohiostate.pressbooks.pub/graphicshistory/chapter/13-2-singer-link/ |publisher=Ohio State University |pages=13.2}}</ref> It was a real-time, 3D capable, day/dusk/night system that was used by NASA shuttles, for F-111s, Black Hawk and the B-52. Link's Digital Image Generator had architecture to provide a visual system that realistically corresponded with the view of the pilot.<ref>{{cite journal |last1=Suminski, Leonard and |first1=Hulin, Paul |title=Computer Generated Imagery Current Technology |journal=U.S. Army Project Manager for Training Devices |date=September 26, 1980 |pages=14–18}}</ref> The basic architecture of the DIG and subsequent improvements contained a scene manager followed by geometric processor, video processor and into the display with the end goal of a visual system that processed realistic texture, shading, translucency capabilities, and free of aliasing.<ref>{{cite web |last1=Yan, Johnson K. and |first1=Florence, Judit K. |title=MODULAR DIGITAL IMAGE GENERATOR |url=https://patents.google.com/patent/US4570233A/en?oq=4%2c570%2c233 |publisher=United States Patent Office |ref=4,570,233}}</ref>
Combined with the need to pair virtual synthesis with military level training requirements, CGI technologies applied in flight simulation were often years ahead of what would have been available in commercial computing or even in high budget film. Early CGI systems could depict only objects consisting of planar polygons. Advances in algorithms and electronics in flight simulator visual systems and CGI in the 1970s and 1980s influenced many technologies still used in modern CGI adding the ability to superimpose texture over the surfaces as well as transition imagery from one level of detail to the next one in a smooth manner.<ref>{{Cite journal |last=Yan |first=Johnson |date=August 1985 |title=Advances in Computer-Generated Imagery for Flight Simulation |journal= IEEE Computer Graphics and Applications|volume=5 |issue=8 |pages=37–51|doi=10.1109/MCG.1985.276213 |s2cid=15309937 }}</ref>
The evolution of CGI led to the emergence of [[virtual cinematography]] in the 1990s, where the vision of the [[Computer simulation|simulated]] [[camera]] is not constrained by the laws of physics. 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.
==Static images and landscapes==
{{See also|Fractal landscape|Scenery generator}}
[[File:FractalLandscape.jpg|thumb|A [[fractal landscape]] created in [[Terragen]]]]
Not only do animated images form part of computer-generated imagery; natural looking landscapes (such as [[fractal landscapes]]) are also generated via computer [[algorithms]]. A simple way to generate fractal surfaces is to use an extension of the [[Polygon mesh|triangular mesh]] method, relying on the construction of some special case of a [[de Rham curve]], e.g., [[midpoint displacement]].{{sfn|Peitgen|2004|pp=462–466}} For instance, the algorithm may start with a large triangle, then recursively zoom in by dividing it into four smaller [[Sierpinski triangle]]s, then interpolate the height of each point from its nearest neighbors.{{sfn|Peitgen|2004|pp=462–466}} The creation of a [[Brownian surface]] may be achieved not only by adding noise as new nodes are created but by adding additional noise at multiple levels of the mesh.{{sfn|Peitgen|2004|pp=462–466}} Thus a [[topographical]] map with varying levels of height can be created using relatively straightforward fractal algorithms. Some typical, easy-to-program fractals used in CGI are the ''plasma fractal'' and the more dramatic ''fault fractal''.<ref>''Game programming gems 2'' by Mark A. DeLoura 2001 {{ISBN|1-58450-054-9}} page 240 [https://books.google.com/books?id=1-NfBElV97IC&dq=fractal+landscape&pg=PA239]</ref>
Many specific techniques have been researched and developed to produce highly focused computer-generated effects — e.g., the use of specific models to represent the chemical weathering of stones to model erosion and produce an "aged appearance" for a given stone-based surface.<ref>''Digital modeling of material appearance'' by [[Julie Dorsey]], [[Holly Rushmeier]], François X. Sillion 2007 {{ISBN|0-12-221181-2}} page 217</ref>
==Architectural scenes==
[[File:Lone House.jpg|thumb|A computer-generated image featuring a house at sunset, made in [[Blender (software)|Blender]]]]
Modern architects use services from computer graphic firms to create 3-dimensional models for both customers and builders. These computer generated models can be more accurate than traditional drawings. [[Architectural animation]] (which provides animated movies of buildings, rather than interactive images) can also be used to see the possible relationship a building will have in relation to the environment and its surrounding buildings. The processing of architectural spaces without the use of paper and pencil tools is now a widely accepted practice with a number of computer-assisted architectural design systems.{{sfn|Sondermann|2008|pages=8–15}}
Architectural modeling tools allow an architect to visualize a space and perform "walk-throughs" in an interactive manner, thus providing "interactive environments" both at the urban and building levels.<ref>''Interactive environments with open-source software: 3D walkthroughs'' by Wolfgang Höhl, Wolfgang Höhl, 2008, {{ISBN|3-211-79169-8}}, pp. 24–29.</ref> Specific applications in architecture not only include the specification of building structures (such as walls and windows) and walk-throughs but the effects of light and how sunlight will affect a specific design at different times of the day.<ref>{{Cite news|url=https://garagefarm.net/blog/light-the-art-of-exposure|title=Light: The art of exposure|date=2020-11-12|work=GarageFarm|access-date=2020-11-12|language=en-US}}</ref><ref>''Advances in Computer and Information Sciences and Engineering'' by Tarek Sobh 2008 {{ISBN|1-4020-8740-3}} pages 136-139</ref>
Architectural modeling tools have now become increasingly internet-based. However, the quality of internet-based systems still lags behind sophisticated in-house modeling systems.<ref>''Encyclopedia of Multimedia Technology and Networking, Volume 1'' by Margherita Pagani 2005 {{ISBN|1-59140-561-0}} page 1027</ref>
In some applications, computer-generated images are used to "reverse engineer" historical buildings. For instance, a computer-generated reconstruction of the monastery at [[Georgenthal]] in Germany was derived from the ruins of the monastery, yet provides the viewer with a "look and feel" of what the building would have looked like in its day.<ref>''Interac storytelling: First Joint International Conference'' by Ulrike Spierling, Nicolas Szilas 2008 {{ISBN|3-540-89424-1}} pages 114-118</ref>
==Anatomical models==
{{see also|Medical imaging|Visible Human Project|Google Body|Living Human Project}}
[[File:SADDLE PE.JPG|thumb|A [[CT pulmonary angiogram]] image generated by a computer from a collection of [[x-ray]]s]]
Computer generated models used in [[skeletal animation]] are not always anatomically correct. However, organizations such as the [[Scientific Computing and Imaging Institute]] have developed anatomically correct computer-based models. Computer generated anatomical models can be used both for instructional and operational purposes. To date, a large body of artist-produced [[Medical imaging|medical image]]s continue to be used by medical students, such as images by [[Frank H. Netter]], e.g. [http://www.netterimages.com/image/671.htm Cardiac images]. However, a number of online anatomical models are becoming available.
A single patient [[X-ray]] is not a computer generated image, even if digitized. However, in applications which involve [[CT scan]]s a three-dimensional model is automatically produced from many single-slice x-rays, producing "computer generated image". Applications involving [[magnetic resonance imaging]] also bring together a number of "snapshots" (in this case via magnetic pulses) to produce a composite, internal image.
In modern medical applications, patient-specific models are constructed in 'computer assisted surgery'. For instance, in total [[knee replacement]], the construction of a detailed patient-specific model can be used to carefully plan the surgery.<ref>''Total Knee Arthroplasty'' by Johan Bellemans, Michael D. Ries, Jan M.K. Victor 2005 {{ISBN|3-540-20242-0}} pages 241-245</ref> These three-dimensional models are usually extracted from multiple [[CT scan]]s of the appropriate parts of the patient's own anatomy. Such models can also be used for planning [[aortic valve]] implantations, one of the common procedures for treating [[heart disease]]. Given that the shape, diameter, and position of the [[Coronary circulation|coronary]] openings can vary greatly from patient to patient, the extraction (from [[CT scan]]s) of a model that closely resembles a patient's valve anatomy can be highly beneficial in planning the procedure.<ref>I. Waechter et al. ''Patient Specific Models for Minimally Invasive Aortic Valve Implantation'' in ''[[Medical Image Computing]] and Computer-Assisted Intervention -- MICCAI 2010'' edited by Tianzi Jiang, 2010 {{ISBN|3-642-15704-1}} pages 526-560</ref>
==Cloth and skin images==
[[File:Wet Fur - CGI.jpg|thumb|Computer-generated wet fur created in [[Autodesk Maya]]]]
[[Cloth modeling|Models of cloth]] generally fall into three groups:
*The geometric-mechanical structure at [[yarn]] crossing
*The mechanics of continuous elastic sheets
*The geometric macroscopic features of cloth.<ref>''Cloth modeling and animation'' by Donald House, David E. Breen 2000 {{ISBN|1-56881-090-3}} page 20</ref>
To date, making the clothing of a digital character automatically fold in a natural way remains a challenge for many animators.<ref>''Film and photography'' by Ian Graham 2003 {{ISBN|0-237-52626-3}} page 21</ref>
In addition to their use in film, advertising and other modes of public display, computer generated images of clothing are now routinely used by top fashion design firms.<ref>''Designing clothes: culture and organization of the fashion industry'' by Veronica Manlow 2007 {{ISBN|0-7658-0398-4}} page 213</ref>
The challenge in rendering [[human skin]] images involves three levels of realism:
*'''Photo realism''' in resembling real [[skin]] at the static level
*'''Physical realism''' in resembling its movements
*'''Function realism''' in resembling its response to actions.<ref>''Handbook of Virtual Humans'' by Nadia Magnenat-Thalmann and Daniel Thalmann, 2004 {{ISBN|0-470-02316-3}} pages 353-370</ref>
The finest visible features such as fine [[wrinkle]]s and skin [[Sweat gland|pore]]s are the size of about 100 [[micrometre|μm]] or 0.1 [[millimetre]]s. Skin can be modeled as a 7-[[dimension]]al [[bidirectional texture function]] (BTF) or a collection of [[bidirectional scattering distribution function]] (BSDF) over the target's surfaces.
When animating a texture like hair or fur for a computer generated model, individual base hairs are first created and later duplicated to demonstrate volume.<ref name=":1">{{Cite web |title=Sullivan fur pattern studies Maquette by Jerome Ranft. Monsters Inc., 2001 {{!}} MoMA |url=https://www.moma.org/audio/playlist/192/2569#:~:text=The%20artists%20debated%20llama%20wool,drawing%20of%20six%20standing%20monsters |access-date=2025-04-24 |website=The Museum of Modern Art |language=en}}</ref> The initial hairs are often different lengths and colors, to each cover several different sections of a model. This technique was notably used in [[Pixar]]’s ''[[Monsters, Inc.|Monsters Inc]]'' (2001) for the character Sulley, who had approximately 1,000 initial hairs generated that were later duplicated 2,800 times.<ref name=":1" /> The quantity of duplications can range from thousands to millions, depending on the level of detail sought after.
==Interactive simulation and visualization==
{{Main|Interactive visualization}}
Interactive visualization is the rendering of data that may vary dynamically and allowing a user to view the data from multiple perspectives. The applications areas may vary significantly, ranging from the visualization of the flow patterns in [[fluid dynamics]] to specific [[computer aided design]] applications.<ref>''Mathematical optimization in computer graphics and vision'' by Luiz Velho, Paulo Cezar Pinto Carvalho 2008 {{ISBN|0-12-715951-7}} page 177</ref> The data rendered may correspond to specific visual scenes that change as the user interacts with the system — e.g. simulators, such as [[flight simulator]]s, make extensive use of CGI techniques for representing the world.<ref name=Weiskopf >''GPU-based interactive visualization techniques'' by Daniel Weiskopf 2006 {{ISBN|3-540-33262-6}} pages 1-8</ref>
At the abstract level, an interactive visualization process involves a "data pipeline" in which the raw data is managed and filtered to a form that makes it suitable for rendering. This is often called the '''"visualization data"'''. The visualization data is then mapped to a "visualization representation" that can be fed to a rendering system. This is usually called a '''"renderable representation"'''. This representation is then rendered as a displayable image.<ref name=Weiskopf /> As the user interacts with the system (e.g. by using joystick controls to change their position within the virtual world) the raw data is fed through the pipeline to create a new rendered image, often making real-time computational efficiency a key consideration in such applications.<ref name=Weiskopf /><ref>''Trends in interactive visualization'' by Elena van Zudilova-Seinstra, Tony Adriaansen, Robert Liere 2008 {{ISBN|1-84800-268-8}} pages 1-7</ref>
==Computer animation==
{{Main|Computer animation}}
{{see also|History of computer animation}}
[[File:Machinima sample reindeer full size.ogg|thumb|right|[[Machinima]] films are, by nature, CGI films.]]
While computer-generated images of landscapes may be static, ''[[computer animation]]'' only applies to dynamic images that resemble a movie. However, in general, the term computer animation refers to dynamic images that do not allow user interaction, and the term [[virtual world]] is used for the interactive animated environments.
Computer animation is essentially a digital successor to the art of [[stop motion]] animation of 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 [[Miniature effect|miniatures]] for effects shots or hiring [[extra (drama)|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.
To create the illusion of movement, an image is displayed on the [[computer display|computer screen]] and repeatedly replaced by a new image which is similar to the previous image, 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]] and [[film|motion pictures]].
==Text-to-image models==
{{excerpt|Text-to-image model}}
==
{{Main|Virtual world}}
[[File:Yellow Submarine Second Life.png|thumb|left|A yellow [[submarine]] in ''[[Second Life]]'']]
[[File:Metallic balls.png|thumb|Metallic balls created in [[Blender (software)|Blender]]]]
A virtual world is an [[Agent-based model|agent-based]] and [[computer simulation|simulated environment]] allowing users to interact with artificially animated characters (e.g [[software agent]]) or with other physical users, through the use of [[avatar (computing)|avatars]]. Virtual worlds are intended for its [[user (computing)|users]] to inhabit and interact, and the term today has become largely synonymous with interactive 3D virtual environments, where the users take the form of [[Avatar (computing)|avatar]]s visible to others graphically.<ref>Cook, A.D. (2009). A case study of the manifestations and significance of social presence in a multi-user virtual environment. MEd Thesis. Available [http://library2.usask.ca/theses/available/etd-09102009-012757/ online]</ref> These avatars are usually depicted as textual, two-dimensional, or [[3D computer graphics|three-dimensional graphical]] representations, although other forms are possible{{sfn|Biocca|Levy|1995|pp=40–44}} (auditory{{sfn|Begault|1994|p=212}} and touch sensations for example). Some, but not all, virtual worlds allow for multiple users.
==In
Computer-generated imagery has been used in courtrooms, primarily since the early 2000s. However, some experts have argued that it is prejudicial. They are used to help judges or the jury to better visualize the sequence of events, evidence or hypothesis.<ref>[https://theconversation.com/computer-generated-images-influence-trial-results-19734 Computer-generated images influence trial results] The Conversation, 31 October 2013</ref> However, a 1997 study showed that people are poor intuitive physicists and easily influenced by computer generated images.<ref name="Kassin">{{cite journal |last1=Kassin |first1=S. M. |year=1997 |title=Computer-animated Display and the Jury: Facilitative and Prejudicial Effects |journal=Law and Human Behavior |volume=40 |issue=3 |pages=269–281 |doi=10.1023/a:1024838715221 |s2cid=145311101}} [http://web.williams.edu/Psychology/Faculty/Kassin/files/kassin_dunn_1997.pdf]</ref> Thus it is important that jurors and other legal decision-makers be made aware that such exhibits are merely a representation of one potential sequence of events.
==Broadcast and live events==
Weather visualizations were the first application of CGI in television. One of the first companies to offer computer systems for generating weather graphics was [[ColorGraphics Weather Systems]] in 1979 with the "LiveLine", based around an [[Apple II]] computer, with later models from ColorGraphics using [[Cromemco]] computers fitted with their [[Cromemco Dazzler|Dazzler]] video graphics card.
It has now become common in weather casting to display full motion video of images captured in real-time from multiple cameras and other imaging devices. Coupled with 3D graphics symbols and mapped to a common virtual geospatial model, these animated visualizations constitute the first true application of CGI to TV.
CGI has become common in sports telecasting. Sports and entertainment venues are provided with see-through and overlay content through tracked camera feeds for enhanced viewing by the audience. Examples include the yellow "[[first down]]" line seen in television broadcasts of [[American football]] games showing the line the offensive team must cross to receive a first down. CGI is also used in association with football and other sporting events to show commercial advertisements overlaid onto the view of the playing area. Sections of [[rugby football|rugby]] fields and [[cricket]] pitches also display sponsored images. Swimming telecasts often add a line across the lanes to indicate the position of the current record holder as a race proceeds to allow viewers to compare the current race to the best performance. Other examples include hockey puck tracking and annotations of racing car performance<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/1jQUkqqnZIc Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20210714184600/https://www.youtube.com/watch?v=1jQUkqqnZIc Wayback Machine]{{cbignore}}: {{Citation|title=Arti AR highlights at SRX -- the first sports augmented reality live from a moving car!| date=14 July 2021 |url=https://www.youtube.com/watch?v=1jQUkqqnZIc|language=en|access-date=2021-07-14}}{{cbignore}}</ref> and snooker ball trajectories.<ref name="recentadvances">[[Azuma, Ronald]]; Balliot, Yohan; Behringer, Reinhold; Feiner, Steven; Julier, Simon; MacIntyre, Blair. [http://www.cc.gatech.edu/~blair/papers/ARsurveyCGA.pdf Recent Advances in Augmented Reality] ''Computers & Graphics'', November 2001.</ref><ref>{{cite news|author=Marlow, Chris|url=http://www.dmwmedia.com/news/2012/04/27/hey-hockey-puck-nhl-preplay-adds-a-second-screen-experience-to-live-games|title=Hey, hockey puck! NHL PrePlay adds a second-screen experience to live games|website=digitalmediawire|date=27 April 2012}}</ref> Sometimes CGI on TV with correct alignment to the real world has been referred to as [[augmented reality]].
== Motion capture ==
{{Main article|Motion capture}}
Computer-generated imagery is often used in conjunction with [[motion capture]] to better cover the faults that come with CGI and animation. {{anchor|Bad CGI}}Computer-generated imagery is limited in its practical application by how realistic it can look. Unrealistic, or badly managed computer-generated imagery can result in the [[uncanny valley]] effect.<ref>{{Cite journal|last1=Palomäki|first1=Jussi|last2=Kunnari|first2=Anton|last3=Drosinou|first3=Marianna|last4=Koverola|first4=Mika|last5=Lehtonen|first5=Noora|last6=Halonen|first6=Juho|last7=Repo|first7=Marko|last8=Laakasuo|first8=Michael|date=2018-11-01|title=Evaluating the replicability of the uncanny valley effect|journal=Heliyon|volume=4|issue=11|pages=e00939|doi=10.1016/j.heliyon.2018.e00939|pmid=30519654|pmc=6260244|bibcode=2018Heliy...400939P |issn=2405-8440|doi-access=free}}</ref> This effect refers to the human ability to recognize things that look eerily like humans, but are slightly off. Such ability is a fault with normal computer-generated imagery which, due to the complex anatomy of the human body, can often fail to replicate it perfectly. Artists can use motion capture to get footage of a human performing an action and then replicate it perfectly with computer-generated imagery so that it looks normal.
In many instances, motion capture is needed to accurately mimic an actor's full body movements while slightly changing their appearance with de-aging. [[De-aging in film and television|De-aging]] is a visual effect used to alter the appearance of an actor, often through facial scanning technologies, [[motion capture]], and photo references. It is commonly used for flashback scenes and cameos to have an actor appear younger. [[Marvel Studios|Marvel]]’s ''[[X-Men: The Last Stand]]'' was the first film to publicly incorporate de-aging, which was used on actors [[Patrick Stewart]] and [[Ian McKellen|Ian Mckellen]] for flashback scenes featuring their characters at a younger age.<ref>{{Cite web |title=Face Off |url=https://www.cgw.com/Publications/CGW/2006/Volume-29-Issue-6-June-2006-/Face-Off.aspx |access-date=2025-04-24 |website=Computer Graphics World}}</ref> The visual effects were done by the company [[Lola Visual Effects|Lola VFX]], and used photos taken of the actors at a younger age as references to later smooth out the wrinkles on their face with use of CGI. Overtime, de-aging technologies have advanced, with films such as ''[[Here (2024 film)|Here]]'' (2024), portraying actors at younger ages through the use of digital AI techniques, scanning millions of facial features and incorporating a number of them onto actors’ faces to alter their appearance.<ref>{{Cite web |last=Giardina |first=Carolyn |date=2023-01-31 |title=Tom Hanks, Robin Wright to Be De-aged in Robert Zemeckis' New Movie Using Metaphysic AI Tool |url=https://www.hollywoodreporter.com/movies/movie-news/metaphysic-ai-tom-hanks-robin-wright-deaged-robert-zemeckis-caa-1235313318/ |access-date=2025-04-24 |website=The Hollywood Reporter |language=en-US}}</ref>
The lack of anatomically correct digital models contributes to the necessity of motion capture as it is used with computer-generated imagery. Because computer-generated imagery reflects only the outside, or skin, of the object being rendered, it fails to capture the infinitesimally small interactions between interlocking muscle groups used in [[fine motor skill]]s like speaking. The constant motion of the face as it makes sounds with shaped lips and tongue movement, along with the facial expressions that go along with speaking are difficult to replicate by hand.<ref>{{Cite journal|last1=Pelachaud|first1=Catherine|author-link= Catherine Pelachaud |last2=Steedman|first2=Mark|last3=Badler|first3=Norman|date=1991-06-01|title=Linguistic Issues in Facial Animation|url=https://repository.upenn.edu/hms/69|journal=Center for Human Modeling and Simulation|issue=69 }}</ref> Motion capture can catch the underlying movement of facial muscles and better replicate the visual that goes along with the audio.
==See also==
{{columns-list|colwidth=22em|
* [[3D modeling]]
* [[Cinema Research Corporation]]
*[[Cel shading]]
* [[Anime Studio]]
* [[Animation database]]
* [[List of computer-animated films]]
* [[Digital image]]
* [[Parallel rendering]]
* [[Photoshop]] is the industry standard commercial digital photo editing tool.
* [[GIMP]], a [[FOSS]] digital photo editing application.
* [[Poser (software)|Poser]] DIY CGI optimized for soft models
* [[Random number generation]]
* [[Ray tracing (graphics)]]
* [[Real-time computer graphics]]
* [[Shader]]
* [[Virtual actor|Virtual human]]
* [[Virtual studio]]
* [[Virtual Physiological Human]]
}}
== References ==
=== Citations ===
{{Reflist|refs=
<ref name="imagen-verge">{{cite news |last1=Vincent |first1=James |title=All these images were generated by Google's latest text-to-image AI |url=https://www.theverge.com/2022/5/24/23139297/google-imagen-text-to-image-ai-system-examples-paper |access-date=May 28, 2022 |work=The Verge |publisher=Vox Media |date=May 24, 2022}}</ref>
}}
==
{{refbegin}}
* {{cite book |last = Begault |first = Durand R. |title = 3-D Sound for Virtual Reality and Multimedia |year = 1994 |publisher = AP Professional |isbn = 978-0-1208-4735-8 }}
* {{cite book |last1 = Biocca |first1 = Frank |last2 = Levy |first2 = Mark R. |title = Communication in the Age of Virtual Reality |year = 1995 |publisher = Lawrence Erlbaum Associates |isbn = 978-0-8058-1549-8 }}
* {{cite book |last1=Peitgen |first1=Heinz-Otto |last2=Jürgens |first2=Hartmut |last3=Saupe |first3 = Dietmar |title = Chaos and Fractals: New Frontiers of Science |year = 2004 |publisher = Springer Science & Business Media |isbn = 978-0-387-20229-7 |ref ={{SfnRef|Peitgen|2004}} }}
* {{cite book |last = Sondermann |first = Horst |title = Light Shadow Space: Architectural Rendering with Cinema 4D |year = 2008 |publisher = Springer |___location = Vienna |isbn = 978-3-211-48761-7 }}
{{refend}}
== External links ==
{{Commons category}}
{{Library resources box|by=no|onlinebooks=no|wikititle=computer-generated imagery}}
* [https://web.archive.org/web/20160818194224/http://design.osu.edu/carlson/history/lessons.html A Critical History of Computer Graphics and Animation] – a course page at [[Ohio State University]] that includes all the course materials and extensive supplementary materials (videos, articles, links).
* [http://www.cg101.com CG101: A Computer Graphics Industry Reference] {{ISBN|073570046X}} Unique and personal histories of early computer graphics production, plus a comprehensive foundation of the industry for all reading levels.
* ''[https://www.wired.com/wired/archive/13.02/fxgods.html F/X Gods]'', by Anne Thompson, Wired, February 2005.
* [http://news.bbc.co.uk/2/hi/programmes/click_online/4025541.stm "History Gets A Computer Graphics Make-Over"] Tayfun King, ''Click'', BBC World News (2004-11-19)
* [https://www.nlm.nih.gov/research/visible/visible_gallery.html NIH Visible Human Gallery]
{{Clear}}
{{3D software}}
{{Fractal software}}
{{Unix–Windows interoperability}}
{{Cinematic techniques}}
{{Special effects}}
{{Portal bar|Animation}}
{{Digital art}}
{{DEFAULTSORT:Computer-Generated Imagery}}
[[Category:Visual effects]]
[[Category:Special effects]]
[[Category:Computer art|imagery]]
[[Category:Articles containing video clips]]
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