The very nature of Architectural Design requires an innumerable number of drafts to be created for the purpose of aiding the creative process and presentation to the clients. CAD software made for Architects can perform these conventional tasks more efficiently. They can also

  • enable perspective views to be integrated into the drafts
  • allow the architect to tackle more complex problems
  • give a competitive edge (many clients look for CAD abilities when hiring an architect.)
With its introduction, CAD quickly moved up in status from being desirable to becoming required in the field of Architecture.

click here for an example of a building designed with the support of CAD


Capabilities of architecture-based CAD systems
CAD has matured so quickly in importance mainly due to the communication it brings. Architectural CAD systems often allow files produced from different systems to be read into the same model, enabling compatibility between the software used by the architect and the contractor. The architectural CAD system that creates the visual model of the edifice contains the related databases needed by the other specialists involved, thus putting the architects in charge of the building’s creation. Most importantly, CAD creates a bridge between the architect and the client by giving the clients the power to participate in the design process. The clients do not need a lot of architectural knowledge to fully understand the CAD-rendered models that
  • offer multiple viewpoints
  • contain several relative position shots
  • are complete with the internal organization (such as the placement of furniture to phones) of the building
  • often include animation, enabling the client to take a virtual tour of the building inside and out.
As technology continues to strive forward, Virtual Reality is increasingly becoming more involved in architecture-based CAD programs. Since its introduction in the late 1980’s, architecture and CAD have played a major role in virtual reality. Around 1995, Matsushita Electronic Industries produced a virtual house with its bases in CAD. Since then, a number of projects that incorporated virtual reality with CAD began to grow.


Architectural CAD packages
The most basic CAD packages permit construction and editing of drawings using
  • geometric primitives
  • parts stored in the computer’s libraries
  • 3D geometric modeling and viewing, usually wire frame and solid modelling.

    Wire frame modelling, still widely used by architects, is known as the "ancestor of contemporary CAD presentation". The nature of wire frame models reveals the underlying structure of the building, thus helping architects check the project's 'buildability'. Due to this ability, wire frame modelling is used for establishing the building's skeleton in the developmental design stages of most CAD programs. Solid modelling is usually utilized for the finished model.

    Despite wire frame modelling's advantages, some architects prefer using solid modelling in the primary stages as well as in the final stage. The difference between wire frames and solid modelling is parallel to the difference between using paper/pencil and a 3D object like wood or foam to construct the initial design. Even if solid modelling is used from beginning to end, the first draft does not look remotely like the finished design. In the beginning stages, the architect is not interested in making the building look realistic, only in outlining the rationale of the design. Keith Williams of Pawson Williams Architect further explains how CAD is used as an abstract design process by saying:
    "The importance of the computer is as an interface between the physical design and the abstract ideas behind it. We are interested in CAD as an architectural tool, not as a tool for building."
    It the later stage of design, realistic elements, like color, lighting, and shadows, are added to help communicate the building design to the client.

    (for more information on geometric modelling, go to the graphics section)


    Visualization in Architecture is key, but it is not the only element involved in the design stage. John Walker, founder of AutoCAD (one of the most widely used CAD software among both architects and other design professionals), relays that a true CAD program would be
    "a system which describes physical objects and knows about the various ways in which they interact."

    Some non-visual questions that must be answered during the design process are
    • what type of materials should be used
    • what functions does the building have to perform (i.e. loads and stresses the building must handle)
    • how will the project be constructed
    • how much will it cost