The Beginnings
The conceptual underpinnings of the BIM system go back to the earliest days of computing. As early as 1962, Douglas C. Englebart gives us an uncanny vision of the future architect in his paper Augmenting Human Intellect.
the architect next begins to enter a series of specifications and data–a six-inch slab floor, twelve-inch concrete walls eight feet high within the excavation, and so on. When he has finished, the revised scene appears on the screen. A structure is taking shape. He examines it, adjusts it… These lists grow into an evermore-detailed, interlinked structure, which represents the maturing thought behind the actual design.
Englebart suggests object based design, parametric manipulation and a relational database; dreams that would become reality several years later. There is a long list of design researchers whose influence is considerable including Herbert Simon, Nicholas Negroponte and Ian McHarg who was developing a parallel track with Geographic Information Systems (GIS). The work of Christopher Alexander would certainly have had an impact as it influenced an early school of object oriented programming computer scientists with Notes on the Synthesis of Form. As thoughtful and robust as these systems were, the conceptual frameworks could not be realized without a graphical interface through which to interact with such a Building Model.
Visualizing the Model
From the roots of the SAGE graphical interface and Ivan Sutherland’s Sketchpad program in 1963, solid modeling programs began to appear building on developments in the computational representation of geometry. The two main methods of displaying and recording shape information that began to appear in the 1970s and 1980s were constructive solid geometry (CSG) and boundary representation (brep). The CSG system uses a series of primitive shapes that can be either solids or voids, so that the shapes can combine and intersect, subtract or combine to create the appearance of more complex shapes. This development is especially important in representing architecture as penetrations and subtractions are common procedures in design, (windows, doors).
The process of design requires a visceral connection to the medium that the designer is working in. This posed another challenge as architects required a way to tell the computer what to do that was less tedious than the punch cards that were used on early computers. The development of light pens, head-mounted displays and various contraptions in the early days of human-computer interaction (HCI) are well documented elsewhere. A rigorous history of HCI from an architectural perspective can be found in Nicholas DeMonchaux’s book, Spacesuit: Fashioning Apollo. The text carves a narrative of the precursors to BIM and CAD technology as they were entwined in the Space Race and Cold War.
