Applying Computers to Design
Many of the individual tasks within the overall design process can be performed using a computer. As each of these tasks is made more efficient, the efficiency of the overall process increases as well. The computer is especially well suited to design in four areas, which correspond to the four stages of the general design process given above. Computers function in the design process through geometric modeling capabilities, engineering analysis calculations,automated evaluative procedures, and automated drafting. Figure 6 illustrates the relationship between CAD technology and the final four stages of the design process.
Geometric modeling is one of the keystones of CAD systems. It uses mathematical descriptions of geometric elements to facilitate the representation and manipulation of graphical images on a computer display screen. While the central processing unit (CPU) provides the ability to quickly make the calculations specific to the element, the software provides the instructions necessary for efficient transfer of information between the user and the CPU.
Three types of commands are used by the designer in computerized geometric modeling. The first type of command allows the user to input the variables needed by the computer to represent basic geometric elements such as points, lines, arcs, circles, splines, and ellipses.
The second type of command is used to transform these elements. Commonly performed transformations in CAD include scaling, rotation, and translation. The third type of command allows the various elements previously created by the first two commands to be joined into a desired shape.
