11-06-2014, 02:13 PM
3D VISUALIZATION IN COMPUTER GRAPHICS
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INTRODUCTION
In the last several years, three-dimensional computer graphics has become a critical technology in the PC world. 3D graphics capability is a prerequisite for two major markets: Computer-aided industrial and mechanical design (for which the majority of workstations and high-end PCs are sold today) and entertainment (especially computer games, which are driving significant new PC hardware and software purchases by consumers).
Computer Graphics: Overview
Computer graphics started with the display of data on hardcopy plotters and Cathode Ray Tube (CRT) screens soon after the introduction of computers themselves. It has grown to include the creation, storage, and manipulation of models and images of objects. These models come from a diverse and expanding set of fields and include physical, mathematical, engineering, architectural, and even conceptual (abstract) structures, natural phenomena and so on. Computer graphics today is largely interactive: The user controls the contents, structures, and appearance of objects and of their displayed images by using input devices such as keyboard, mouse, and touch-sensitive panel on screen.
Until the early 1980s, Computer Graphics was a small, specialized field, largely because the hardware was expensive and graphics based application programs that were easy to use and cost-effective were few. Then, personal computers with built in raster graphics displays – such as the Xerox star and, latter the mass produced and less expensive Apple Macintosh and the IBM PC and its clones – popularized the use of bitmap graphics for user-computer interaction. A bitmap is a ones and zeros representation of rectangular array of points (pixels) on the screen. Once bitmap graphics became affordable, an explosion of easy-to-use and inexpensive graphics based applications soon followed. Graphics based user interfaces allowed millions of new users to control simple, low cost application programs, such as spreadsheets, word processors and drawing programs.
The Advantages of Interactive Graphics
Graphics provide one of the most natural means of communicating with computer since our highly developed 2D and 3D pattern-recognition abilities allow us to perceive and process pictorial data rapidly and efficiently. In many design, implementation, and construction processes today, the information pictures can give is virtually indispensable. Scientific visualization became an important field in the late 1980s, when scientists and engineers realized that they could not interpret the prodigious quantities of data produced in supercomputer runs without summarizing the data and highlighting trends and phenomena in various kinds of graphical representations.
Creating and reproducing pictures, however, presented technical problems that stood in the way of their wide spread use. Thus, the ancient Chinese proverb-“a picture is worth ten thousand words” became a cliché in our society only after the advent of inexpensive and simple technology for producing pictures- first the printing press, then photography.
Computer aided drafting and design:
In computer-aided design (CAD), interactive graphics is used to design components and systems of mechanical, electrical, electromechanical, and electronic devices, including structures such as buildings, automobile bodies, airplane and ship hulls, very large-scale-integrated (VLSI) chips, optical systems and telephone and computer networks. Sometimes the user merely wants to produce the precise drawings of components and assemblies, as for online drafting or architectural blueprints. More frequently, however, the emphasis is on interacting with a computer-based model of the component or system being designed in order to test, for example, it’s structural, electrical, thermal properties. Often, the model is interpreted by a simulator that feeds back the behavior of the system to the user for further interactive design and test cycles. After objects have been designed, utility programs can post process the design database to make parts lists, to process ‘bills of materials’, to define numerical control tapes for cutting or drilling parts, and so on.