- See also: Computer-generated imagery
Computer animation is the art of creating moving images via the use of computers. Computer animation Computer-generated imagery (also known as CGI) is the application of the field of Computer graphics or more specifically 3D computer graphics Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model A computer is a Machine that manipulates data according to a list of instructions. It is a subfield of computer graphics and animation. Computer graphics are Graphics created by Computers and more generally the Representation and Manipulation of Pictorial Data The bouncing ball animation (below consists of these 6 frames Increasingly it is created by means of 3D computer graphics, though 2D computer graphics are still widely used for stylistic, low bandwidth, and faster real-time rendering needs. 3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data that is stored in the computer 2D computer graphics is the Computer -based generation of Digital images mdashmostly from two-dimensional models (such as 2D geometric models text and digital Sometimes the target of the animation is the computer itself, but sometimes the target is another medium, such as film. A data storage device is a device for recording (storing information (data It is also referred to as CGI (Computer-generated imagery or computer-generated imaging), especially when used in films. Computer animation Computer-generated imagery (also known as CGI) is the application of the field of Computer graphics or more specifically 3D computer graphics
To create the illusion of movement, an image is displayed on the computer screen then quickly replaced by a new image that is similar to the previous image, but shifted slightly. A visual display unit, often called simply a monitor or display, is a piece of Electrical equipment which displays images generated from the Video This technique is identical to how the illusion of movement is achieved with television and motion pictures. Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic
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. Stop motion (or frame-by-frame) animation is an Animation technique to make a physically manipulated object appear to move on its own 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 frames. A key frame in Animation and Filmmaking is a drawing which defines the starting and ending points of any smooth transition. The differences in appearance between key frames are automatically calculated by the computer in a process known as tweening or morphing. Tweening, short for in-betweening is the process of generating intermediate frames between two images to give the appearance that Morphing is a Special effect in motion pictures and Animations that changes (or morphs one Image into another through a seamless transition Finally, the animation is rendered. Rendering is the process of generating an image from a model, by means of computer programs
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, X3D) often use software on the end-users computer to render in real time as an alternative to streaming or pre-loaded high bandwidth animations. Adobe Flash (previously called Shockwave Flash and Macromedia Flash) is a set of Multimedia software created by Macromedia and currently X3D is the ISO standard XML -based File format for representing 3D computer graphics, the successor to the Virtual Reality Modeling
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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 and color often require calculations and computer rendering instead of simple re-drawing or duplication. Rendering is the process of generating an image from a model, by means of computer programs
Explanation
To trick the eye and brain into thinking they are seeing a smoothly moving object, the pictures should be drawn at around 12 frames per second or faster (a frame is one complete image). Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain Frame rate, or frame frequency, is the measurement of the Frequency (rate at which an imaging device produces unique consecutive images called frames The With rates above 70 frames/s no improvement in realism or smoothness is perceivable due to the way the eye and brain process images. The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain At rates below 12 frames/s most people can detect jerkiness 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.
The reason no jerkiness is seen at higher speeds is due to “persistence of vision. Persistence of vision is the phenomenon of the eye by which even nanoseconds of exposure to an image result in milliseconds of reaction (sight from the retina to the optic nerves ” From moment to moment, the eye and brain working together actually store whatever you look at for a fraction of a second, and automatically "smooth out" minor jumps. Movie film seen in theaters in the United States runs at 24 frames per second, which is sufficient to create this illusion of continuous movement.
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 or stick figure. In Biology, the skeleton is a strong and often a rigid framework that supports the body of an animal holding it upright and giving it shape and strength (Also skeletal A stick figure is a very simple type of drawing made of sticks and circles generally of the Human form although stick figures of other types of Animals are possible The position of each segment of the skeletal model is defined by animation variables, or Avars
In human and animal characters, many parts of the skeletal model correspond to actual bones, but skeletal animation is also used to animate other things, such as facial features (though other methods for facial animation exist). An avar or animation variable (or hinge is a variable controlling the position of part of an animated object, such as a character Skeletal animation, sometimes referred to as rigging is a technique in Computer animation, particularly in the animation of Vertebrates, in which a character is represented Computer facial animation is primarily an area of Computer graphics that encapsulates models and techniques for generating and animating images of the human Head The character "Woody" in Toy Story, for example, uses 700 Avars, including 100 Avars in the face. Toy Story is a 1995 American computer-generated Comedy film, directed by John Lasseter and starring Tom Hanks The computer does not usually render 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. Rendering is the process of generating an image from a model, by means of computer programs 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' between them, a process called keyframing. Tweening, short for in-betweening is the process of generating intermediate frames between two images to give the appearance that A key frame in Animation and Filmmaking is a drawing which defines the starting and ending points of any smooth transition. Keyframing puts control in the hands of the animator, and has roots in hand-drawn traditional animation. Traditional animation, also referred to as classical animation, cel animation, or hand-drawn animation, is the oldest and historically the most popular
In contrast, a newer method called motion capture makes use of live action. Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model 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 cameras and markers, and that performance is then applied to the animated character. A video camera is a Camera used for electronic Motion picture acquisition initially developed by the Television industry but now common in other applications
Each method has their 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, actor Bill Nighy provided the performance for the character Davy Jones. Pirates of the Caribbean Dead Man's Chest is a 2006 Adventure film of the ''Pirates of the Caribbean'' series, the sequel to the 2003 William Francis "Bill" Nighy (ˈnaɪ born 12 December 1949) is a Golden Globe - and BAFTA -award winning English Actor See " Dead Man's Chest ", for the fictional chest which plays a major role in Pirates of the Caribbean Dead Man's Chest. 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.
Computer animation development equipment
Computer animation can be created with a computer and animation software. Some examples of animation software are: Amorphium, Art of Illusion, Poser, Ray Dream Studio, Bryce, Maya, Blender, TrueSpace, Lightwave, 3D Studio Max, SoftImage XSI, Alice, and Adobe Flash (2D). Art of Illusion is a software package used for 3D modeling, texturing, Ray tracing, and otherwise rendering Computer generated Poser is a 3D rendering and animation software program optimized for models that depict the human figure in three-dimensional form Ray Dream Studio was a low-end 3d modeling Software application Bryce is a 3D modeling, rendering and animation program specializing in Fractal landscapes The name is taken from Bryce Canyon Maya is a high-end 3D computer graphics and 3D modeling software package originally developed by Alias Systems Corporation, but now owned by Blender is a free 3D graphics application It can be used for modeling, UV unwrapping texturing rigging, water simulations trueSpace is free 3D computer graphics and animation software developed by Caligari Corporation. LightWave 3D is a high end Computer graphics program developed by NewTek. 3ds Max (formerly 3D Studio MAX) is a modeling animation and rendering package developed by Autodesk Media and Entertainment. Softimage Co ("Softimage" is pronounced /sɑftɪˈmɑʒ/ (US pronunciation or /sɒftɪˈmɑːʒ/ (UK pronunciation is a Alice is a free and Open source object-oriented Educational programming language with an integrated development environment (IDE Adobe Flash (previously called Shockwave Flash and Macromedia Flash) is a set of Multimedia software created by Macromedia and currently There are many more software options available. Prices will vary greatly depending on target market. Some impressive animation can be achieved even with basic programs; however, the rendering 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 computers are used instead. A workstation, such as a Unix workstation, RISC workstation or Engineering workstation, is a high-end Microcomputer Graphics workstation computers use two to four processors, and thus are a lot more powerful than a home computer, and are specialized for rendering. A large number of workstations (known as a render farm) are networked together to effectively act as a giant computer. A render farm is a Computer cluster built to render Computer-generated imagery (CGI typically for film and television Visual effects, using 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. Pixar's Renderman is rendering software which is widely used as the movie animation industry standard, in competition with Mental Ray. Pixar Animation Studios is a CGI animation production company based in Emeryville California. mental ray is a production-quality rendering application developed by mental images (Berlin Germany It can be bought at the official Pixar website for about $5,000 to $8,000. It will work on Linux, Mac OS X, and Microsoft Windows based graphics workstations along with an animation program such as Maya and Softimage XSI. Linux (commonly pronounced ˈlɪnəks Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. Professionals also use digital movie cameras, motion capture or performance capture, bluescreens, film editing software, props, and other tools for movie animation. This article is about motion picture film cameras See Video camera for cameras which record images electronically Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model Chroma Key is the name under which ex- Dream Theater Keyboardist Kevin Moore records A theatrical property, commonly referred to as a prop, is any object held or used on stage by an Actor for use in furthering the plot or story line of a Theatrical
The future
One open challenge in computer animation is a photorealistic animation of humans. Currently, most computer-animated movies show animal characters (Finding Nemo), fantasy characters (Shrek, Monsters Inc.), anthropomorphic machines (Cars, Robots) or cartoon-like humans (The Incredibles). Finding Nemo is a 2003 computer-animated American Family film. Shrek is a 2001 computer-animated American Comedy film, directed by Andrew Adamson and Vicky Jenson, and Monsters Inc is a 2001 Computer animated Comedy film and the fourth feature-length film produced by Pixar Animation Studios. Anthropomorphism is the attribution of uniquely Human characteristics to non-human creatures and beings natural and supernatural phenomena material states and objects Cars is a 2006 animated Feature film produced by Pixar and directed by both John Lasseter and Joe Ranft. Robots is a 2005 American computer-animated Comedy film produced by Blue Sky Studios for 20th Century Fox (the The Incredibles is a 2004 Computer-animated feature Film produced by Pixar Animation Studios for Walt Disney Pictures, The movie Final Fantasy: The Spirits Within is often cited as the first computer-generated movie to attempt to show realistic-looking humans. Final Fantasy The Spirits Within is a Science fiction film by Hironobu Sakaguchi, the creator of the Final Fantasy series of However, due to the enormous complexity of the human body, human motion, and human biomechanics, realistic simulation of humans remains largely an open problem. 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, however such concepts obviously bear certain philosophical implications for the future of 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. Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model 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 without having to use advanced puppetry and animatronics, while Antz is an example on stylistic photorealism (in the future stylized photorealism will be able to replace traditional stop motion animation as in Corpse Bride). The Dark Crystal is a 1982 Fantasy film directed by Jim Henson and Frank Oz. Antz is a 1998 computer-animated Film produced by DreamWorks. None of them are as mentioned perfected 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. Disney's Nine Old Men were the core Animators (some of whom later became directors who created the Disney studio 's most famous works from Snow
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 ever simpler look). Cel-shaded animation (also called cel-shading or toon shading) is a type of Non-photorealistic rendering designed to make Computer graphics appear
Detailed examples and pseudocode
In 2D computer animation, moving objects are often referred to as “sprites. In Computer graphics, a sprite (also known by other names see Synonyms below is a two-dimensional/three-dimensional Image or Animation that ” 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 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
Modern (2001) computer animation uses different techniques to produce animations. Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. Most frequently, sophisticated mathematics is used to manipulate complex three dimensional polygons, apply “textures”, lighting and other effects to the polygons and finally rendering the complete image. Mathematics is the body of Knowledge and Academic discipline that studies such concepts as Quantity, Structure, Space and In Geometry a polygon (ˈpɒlɨɡɒn ˈpɒliɡɒn is traditionally a plane figure that is bounded by a closed path or circuit Texture mapping is a method for adding detail surface texture or colour to a computer-generated graphic or 3D model. Rendering is the process of generating an image from a model, by means of computer programs A sophisticated graphical user interface may be used to create the animation and arrange its choreography. Another technique called constructive solid geometry defines objects by conducting boolean operations on regular shapes, and has the advantage that animations may be accurately produced at any resolution. Constructive solid geometry (CSG is a technique used in Solid modeling.
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 ‘farthest’ 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” is often used. Texture mapping is a method for adding detail surface texture or colour to a computer-generated graphic or 3D model. A small drawing of wood that can be repeatedly drawn in a matching tiled pattern (like wallpaper) is stretched and drawn onto the walls' final shape. This page refers to the material used for Interior decoration. 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 since 1976, though the popularity of computer animation (especially in the field of special effects) skyrocketed during the modern era of U.S. animation. Independent animation is a term used to describe animated short cartoons and feature films produced outside the professional Hollywood animation industry The illusions used in the Film, Television, Theater, or Entertainment industries to simulate the imagined events in a story are traditionally called Modern animation of the United States describes the history of Animation in the United States of America from the late 1980s to the start of the 21st century The first completely computer-generated television series was ReBoot, and the first completely computer-generated animated movie was Toy Story, in 1994 and 1995 respectively. ReBoot is a Canadian CGI - animated action-adventure Television series that originally aired from 1994 to 2001 Toy Story is a 1995 American computer-generated Comedy film, directed by John Lasseter and starring Tom Hanks See List of computer-animated films for more. A computer-animated film commonly refers to Feature films that have been computer-animated to appear three dimensional on a movie screen
Amateur animation
The popularity of sites such as YouTube, which allows members to upload their own movies for others to view, has created a growing number of what is often considered amateur computer animators. YouTube is a video sharing website where users can upload view and share Video clips YouTube was created in February 2005 by three former PayPal employees An amateur is generally considered a person attached to a particular pursuit study or science without formal training or pay With many free utilities available and programs such as Windows Movie Maker, anyone with the tools can have their animation viewed by thousands. Many high end animation software is also available on a trial basis, allowing for educational and non-commercial development with certain restrictions. One way to create amateur animation is using the GIF format, which can be uploaded and seen on the web easily. GIF animating software include Beneton Movie GIF, GIF Movie Gear, Ulead GIF Animator, and more.
Architectural animation
Architects use services from animation companies to create a 3-dimensional models for both the customers and builders. It can be more accurate than traditional drawings. Architectural animation can also be used to see the possible relationship the building will have in relation to the environment and its surrounding buildings. Architectural Animation is usually a short architectural movie created on a computer
See also
- Animation
- Computer-generated imagery (CGI)
- Computer Graphics Lab
- DreamWorks Animation SKG
- National Centre for Computer Animation (UK)
- Wire frame model
- Virtual artifact
- Computer representation of surfaces
- Motion capture
- Avar (animation variable)
- Pixar Animation Studios
- Rhythm and Hues Studios
- Skeletal animation
- Morph target animation
- Timeline of CGI in film and television
- List of computer-animated films
Animated images in Wikipedia
- Computer animation example
- An animated pentakisdodecahedron
- Animation of an MRI brain scan, starting at the top of the head and moving towards the base
External links
- 3dTune - 3D short animations
- CG101: A Computer Graphics Industry Reference. Terrence Masson. ISBN# 073570046X Histories of early computer graphics production
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