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. It is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in a number of ways. The most common method of presenting animation is as a motion picture or video program, although several other forms of presenting animation also exist. Traditional animation Main article: Traditional animation An example of traditional animation, a horse animated by rotoscoping from Eadweard Muybridge's 19th century photos. (Also called cel animation or hand-drawn animation) Traditional animation was the process used for most animated films of the 20th century. The individual frames of a traditionally animated film are photographs of drawings, which are first drawn on paper. To create the illusion of movement, each drawing differs slightly from the one before it. The animators' drawings are traced or photocopied onto transparent acetate sheets called cels, which are filled in with paints in assigned colors or tones on the side opposite the line drawings. The completed character cels are photographed one-by-one onto motion picture film against a painted background by a rostrum camera. The traditional cel animation process became obsolete by the beginning of the 21st century. Today, animators' drawings and the backgrounds are either scanned into or drawn directly into a computer system. Various software programs are used to color the drawings and simulate camera movement and effects. The final animated piece is output to one of several delivery mediums, including traditional 35 mm film and newer media such as digital video. The "look" of traditional cel animation is still preserved, and the character animators' work has remained essentially the same over the past 70 years. Some animation producers have used the term "tradigital" to describe cel animation which makes extensive use of computer technology. Examples of traditionally animated feature films include Pinocchio (United States, 1940), Animal Farm (United Kingdom, 1954), and Akira (Japan, 1988). Traditional animated films which were produced with the aid of computer technology include The Lion King (US, 1994) Sen to Chihiro no Kamikakushi (Spirited Away) (Japan, 2001), and Les Triplettes de Belleville (2003). * Full animation refers to the process of producing high-quality traditionally animated films, which regularly use detailed drawings and plausible movement. Fully animated films can be done in a variety of styles, from realistically designed works such as those produced by the Walt Disney studio, to the more "cartoony" styles of those produced by the Warner Bros. animation studio. Many of the Disney animated features are examples of full animation, as are non-Disney works such as The Secret of NIMH (US, 1982) and The Iron Giant (US, 1999) * Limited animation involves the use of less detailed and/or more stylized drawings and methods of movement. Pioneered by the artists at the American studio United Productions of America, limited animation can be used as a method of stylized artistic expression, as in Gerald McBoing Boing (US, 1951), Yellow Submarine (UK, 1968), and much of the anime produced in Japan. Its primary use, however, has been in producing cost-effective animated content for media such as television (the work of Hanna-Barbera, Filmation, and other TV animation studios) and later the Internet (web cartoons). * Rotoscoping is a technique, patented by Max Fleischer in 1917, where animators trace live-action movement, frame by frame. The source film can be directly copied from actors' outlines into animated drawings, as in The Lord of the Rings (US, 1978), used as a basis and inspiration for character animation, as in most Disney films, or used in a stylized and expressive manner, as in Waking Life (US, 2001) and A Scanner Darkly (US, 2006). Stop motion A clay animation scene from a TV commercial. * Stop-motion animation * Clay animation, or Plasticine animation * Cutout animation * Graphic animation * Model animation * Object animation * Pixilation * Puppet animation Computer animation encompasses a variety of techniques, the unifying factor being that the animation is created digitally on a computer. 2D animation 2D animation figures are created and/or edited on the computer using 2D bitmap graphics or created and edited using 2D vector graphics. This includes automated computerized versions of traditional animation techniques such as of tweening, morphing, onion skinning and interpolated rotoscoping. * Analog computer animation * Flash animation * PowerPoint animation 3D animation 3D animation digital models manipulated by an animator. In order to manipulate a mesh, it is given a digital skeletal structure that can be used to control the mesh. This process is called rigging. Various other techniques can be applied, such as mathematical functions (ex. gravity, particle simulations), simulated fur or hair, effects such as fire and water and the use of Motion capture to name but a few, these techniques fall under the category of 3d dynamics. Many 3D animations are very believable and are commonly used as Visual effects for recent movies. Terms * Cel-shaded animation * Morph target animation * Non-photorealistic rendering * Skeletal animation * Motion capture * Crowd simulation 2D animation techniques tend to focus on image manipulation while 3D techniques usually build virtual worlds in which characters and objects move and interact. 3D animation can create images that seem real to the viewer. Other animation techniques * Drawn on film animation * Paint-on-glass animation * Pinscreen animation * Sand animation * Flip book