Moving from manual drafting to computer-aided design and drafting was an important step in terms of the potential of today’s technology. CAD originally meant computer-aided drafting because of its original use as a replacement for traditional drafting. Now it usually refers to computer-aided design to reflect the fact that modern CAD tools do more than just drafting (Figures 2.5A, B, and C). Related acronyms are CADD, which stands for computer-aided design and drafting; CAID, for computer-aided industrial design; and CAAD, for computer-aided architectural design. All of these terms are essentially synonymous, but there are a few subtle differences in meaning and application. CAM (computer-aided manufacturing) is also often used in a similar way or as a combination (CAD/CAM).
When we use computer-aided design and drafting (CADD), certain questions arise that we never think of when working on the drawing board. Although with CAD or CADD we do not use the typical drawing-board tools, we are still required to design or make a drawing.
CADD is an electronic tool that enables you to rapidly create accurate drawings with the use of a computer. In fact, an experienced computer drafter can normally produce a construction drawing in less time than it would take if it was done manually. Moreover, unlike the traditional methods of making drawings on a drawing board, with CADD systems you can create professional drawings just by using a mouse and clicking buttons on the keyboard. Furthermore, drawings created with CADD have many advantages over traditionally produced drawings. In addition to the fact that they are neat, accurate, and highly presentable, they can be easily modified and converted to a variety of formats. In addition, CADD-generated drawings can be saved on the computer, a flash, a CD, or an external hard drive in lieu of vellum or Mylar sheets that require the use of large storage cabinets for filing.
A decade ago CADD was largely used for specific engineering applications that required high precision, and because of CADD’s high production costs, not many professionals could afford it. In recent years, however, computer prices have dropped significantly, and professionals are increasingly taking advantage of this by adopting CADD programs.
There is a wealth of CADD programs available on the market today. Some are intended for general drawing work, while others are designed for specific engineering applications. There are programs that enable you to do 2D drawings, 3D drawings, renderings, shadings, punch lists, space planning, structural design, piping layouts, HVAC, plant design, project management, and other applications. Today we can find a CADD program for almost every engineering discipline that comes to mind.
Although CADD is primarily intended for single-line drafting and has very limited capabilities to create artistic impressions, CADD’s 3D and rendering features are quite impressive. A 3D model of an object can be created and viewed from various angles and, with correct shading and rendering, can be made to look very realistic. With CADD you can create fine drawings with hundreds of colors, line types, hatch patterns, presentation symbols, text styles, and other features. Even if you don’t like something about your presentation after you have finished it, you can instantly change it (Figure 2.6).
Most CADD programs have a number of ready-made presentation symbols and hatch patterns available that can be used to enhance the look of drawings. When drawing a site plan, for example, a draftsperson can instantly add tree symbols, shrubs, pathways, human figures, and other landscape elements to create a professional-looking site plan. Similarly, an architect can use ready-made symbols