Computer-generated imagery

Computer-generated imagery (CGI) is the application of computer graphics to create or contribute to images in art, printed media, video games, films, television programs, shorts, commercials, videos, and simulators. The visual scenes may be dynamic or static and may be two-dimensional (2D), though the term 'CGI' is most commonly used to refer to 3D computer graphics used for creating scenes or special effects in films and television. Additionally, the use of 2D CGI is often mistakenly referred to as 'traditional animation', most often in the case when dedicated animation software such as Adobe Flash or Toon Boom is not used or the CGI is hand drawn using a tablet and mouse. Computer-generated imagery (CGI) is the application of computer graphics to create or contribute to images in art, printed media, video games, films, television programs, shorts, commercials, videos, and simulators. The visual scenes may be dynamic or static and may be two-dimensional (2D), though the term 'CGI' is most commonly used to refer to 3D computer graphics used for creating scenes or special effects in films and television. Additionally, the use of 2D CGI is often mistakenly referred to as 'traditional animation', most often in the case when dedicated animation software such as Adobe Flash or Toon Boom is not used or the CGI is hand drawn using a tablet and mouse. The term 'CGI animation' refers to dynamic CGI rendered as a movie. The term virtual world refers to agent-based, interactive environments. Computer graphics software is used to make computer-generated imagery for films, etc. 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. This has brought about an Internet subculture with its own set of global celebrities, clichés, and technical vocabulary. The evolution of CGI led to the emergence of virtual cinematography in the 1990s where runs of the simulated camera are not constrained by the laws of physics. 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 triangular mesh method, relying on the construction of some special case of a de Rham curve, e.g. midpoint displacement. For instance, the algorithm may start with a large triangle, then recursively zoom in by dividing it into four smaller Sierpinski triangles, then interpolate the height of each point from its nearest neighbors. 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. 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. A large number of 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. 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 rendering 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. 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. 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. Architectural modeling tools have now become increasingly internet-based. However, the quality of internet-based systems still lags behind that of sophisticated in-house modeling systems. 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. 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 images continue to be used by medical students, such as images by Frank H. Netter, e.g. Cardiac images. However, a number of online anatomical models are becoming available.