The changing pace of design and technology within the construction industry has inevitably led to a certain amount of confusion along the way. As new methods, processes and software arrive, some will manifest as developments of older forms while others might develop in parallel — seeming superficially similar but in fact intended to be used for distinctly different applications. Others are complementary but with definite unique qualities that can be overlooked by the layperson.
The confusion regarding CAD, BIM and VDC is a case in point. The most frequently heard question regarding BIM from those unfamiliar with the process is: "isn't that just 3D CAD?" Similarly, VDC is often mistaken for BIM and vice versa. To some degree, it all depends on which technology or process a user has first become familiar with. To those that are up to speed with all three, however, the distinctions are quite clear.
Understanding CAD
CAD, or Computer Assisted Design, is the oldest methodology of the three. This is a design and documentation tool that uses computer technology to arrive at the most accurate, comprehensive and information-rich model within its parameters. It is typically used for designing and engineering complex projects, from mobile phones to aeroplanes to buildings, which include multiple precision parts and components.
CAD utilizes both 2D drawings and 3D models. 3D CAD has been standard in manufacturing since the 1990s and has benefited the industry enormously in terms of allowing more complex design work to be executed quickly and more efficiently. Its widespread adoption was largely driven by the need for businesses to remain competitive, as 3D CAD enabled products to be delivered to market a lot faster than before, and so any company not using 3D CAD would inevitably lag behind. 3D CAD has been increasingly used for the design of buildings.