CAD Drafting – Changes in 2D and 3D Design
CAD or computer-aided design has been around since the 1980’s.
The early versions of CAD were all 2D CAD. These programs become popular quickly because of their affordability and their ability to run on personal computers. More importantly, CAD programs enabled engineers to do their own drafting work as part of the design process. This elimination of drafting personnel was a first step in reducing design overhead, in both financial cost and time cost.
Today’s CAD software packages may focus on the traditional 2D drafting systems (vector drafting) or they may be 3D design systems which deal in solid and surface models. Some modern CAD packages even allow rotations in three dimensions, allowing viewing of a designed object from any angle. Some modern CAD software is capable of dynamic mathematical modeling, in which case it may be marketed as CADD, which stands for computer-aided design and drafting.
Different types of CAD require the CAD operator to think differently about how to use them to design.
Lower-end 2D systems provide an approach to the drawing process that is similar to the old-school hand drafting but without concern over scale and placement on the drawing sheet that accompanied hand drafting. Computerized drafting enables scale and placement to be adjusted as required during the creation of the final draft.
Higher-end 3D systems require the CAD operator to use what is referred to as “design intent”. Sean Dotson of Autodesk defines design intent as “the act of capturing intelligence in your model by means of parametric and geometric relationships that define the fit and function of the part.”
Design intent provides a “perfect world” representation of the component that enables future revisions and changes of one section within the model to be interpreted throughout the design so that the engineer can see the results of the change in the overall design, rather than just as a basic shape change in one section. This means that the designer must consider the consequences of any changes that he makes.
CAD has truly come a long way in the years since its introduction in the 1980’s. According to Wikipedia, CAD is used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising, and technical manuals. Even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics (both hardware and software), and discrete differential geometry.