Computer-Aided Design (CAD) geometric modeling has been used in architecture for several decades. From its simple beginning, it has now become mature and powerful. This paper presents the basic methodologies of geometric modeling supporting the latest CAD applications, an overview of the basic theoretical foundations of CAD modeling and how the forms and geometries can be topologically and parametrically modeled. It also covers an overview of parametric (generative) design tools that are being used in architecture.

The world’s first interactive Computer-Aided Design (CAD) system is credited to Ivan Sutherland who developed special graphics hardware and a program called ‘Sketchpad’ for his Ph.D. dissertation in 1963 (Eastman, 1999). Over the years, CAD has evolved and developed in an evolutionary manner in which the development of algorithms for drawing curves, panning and scaling images are further intensely researched. Many researches are focused on the development of building use, such as representation and manipulation of geometry.

Geometric modeling has been an interesting subject for many years from mathematical and computer science view points and also from the standpoint of engineering and various other applications (Kimura, 1998). Geometric modeling is defined as the construction of shapes and forms for the purpose of representation of physical objects. In many ways, it is being constructed for the use of different disciplines like computer graphics, architecture, engineering, manufacturing and other applied fields like medical image processing. In general, 2D and 3D geometric models are extensively used in computer graphics, architecture and engineering for representation, for accurate production of working drawings, manufacturing and precise fabrication.

Conventional CAD systems focus attention on the representation of the object being designed. Currently, industry attention is on systems where concept designed buildings are represented parametrically (Aish and Woodburry, 2005). The efficient use of parametric tools help architects to generate parametric model of structure and also for the concept design that guides variation. The most positive outcome of parameterization in architecture is that architects can create a model of a building not only for the primary purpose of form transformations, but also for performative architecture-structural, climatic and financial issues. Parameterization enhances the search for better designs and is more adapted to an underlying context of architecture to facilitate discovery of new forms. The current trend of form making has reduced time and effort required for change and reuse of models. This has resulted in a better collaboration and understanding between the architect as the main designer and other allied engineering disciplines.

Architecture Journal Computer-Aided Design (CAD), Geometric Modeling, Parametric Modeling, Solid Modeling, Surface Modeling, Parametric Design, Software Solution, Graphical Algorithm, Design Methodology.