Graphics Designing is one of my favourite interests (see My Graphics gallery). Computer Graphics, are images created by using a computer. Computer graphics are used in a variety of fields, including entertainment, science, education, medicine, business, and industry. Computer graphics also help make computers easier to use. Graphical user interfaces (GUIs) allow computer users to interact with their computers by selecting small images called icons to execute instructions, eliminating the need to use text commands.
Creating a computer-generated image generally follows three separate stages: modeling, rendering, and display. These stages result in a completed image.
A Modeling Stage
In the first stage of assembling a computer graphic, known as the modeling stage, a computer graphics artist acquires enough data to represent an image in three dimensions (3D). The data are usually grouped into three distinct classes, according to how the data are acquired. The first class of data is geometric and is usually created with special modeling software or acquired by using a 3D scanner, a device that converts an image or model into digital data. Objects such as buildings, for example, are approximated with a set of simple shapes such as triangles and spheres. The second class of data involves placing acquired images, usually from a camera or a video recorder, in 3D space. The third class relates to volume data, such as that acquired from a CAT scan. This type of data is mostly used in medical applications.
B Rendering Stage
During the second stage of image creation, known as the rendering stage, a two-dimensional image is produced from the three-dimensional input data. The method with which an image is rendered depends on the type of input data, the quality of the desired image, and the amount of time needed to render the image. For example, high-quality computer graphics images that are indistinguishable from a photograph take about 24 hours to render. Low-quality images, such as the type used in video games, can be rendered in 1/60 of a second. For geometric data, the rendering process may be as simple as projecting all the objects onto the computer’s screen, or it may be as complex as a full lighting simulation involving dozens of light sources. The process is similar to placing a large sheet of glass in a room and having an artist paint everything seen through the glass onto the glass. Only in computer graphics that sheet of glass is the computer monitor, the artist is the computer itself, and the brushstrokes are guided by mathematical formulas. The end result of the rendering stage is an image that consists of a large number of colored picture elements known as pixels arranged in a grid like the squares on a sheet of graph paper. Together, these pixels form the image.
C Display Stage
The final stage in creating a computer graphics image is the display stage. It involves making the image suitable for display. Although the rendering stage produces two-dimensional data, which would theoretically be suitable for display on computer monitors or in computer printouts, further processing is needed for various purposes. For example, the colors of phosphor available for the image on the computer monitor are different from the colors of ink available in the printer. Therefore, during the display stage the computer graphics artist may change the color representation of the image so that the printed image will look the same as it does on the monitor.