A Conversation About BIM
This post focuses on one of the reasons, a current failing for most BIM, and a wonderful capacity of human intelligence that will not be replaced soon: the ability to operate at multiple scales.
Briefly, BIM is a method of describing an architectural design with a large database. Vaguely, buildings are a collection of slabs, walls, and roofs, and each of these elements themselves may have components attached to them, like windows, doors, and openings. In BIM, each component is modeled spatially, (i.e. a door is 1’-0” south on this wall from the intersection with this wall.) but this relational information is in some ways secondary to the way the building’s information is stored: a BIM is just a complicated database of individually customized components and the “models” we see are odd windows into that database.
It may seem like a non- sequitur, but it is helpful to talk first about how others value models before diving into a critique of BIM. In A Brief History of Time, Steven Hawking defends some of his most important work he did (in the 70’s), making cosmological theories by studying the idealized behavior of sub-atomic particles…
“I would like to emphasize that this idea that time and space should be finite without boundary is just a proposal: it cannot be deduced from some other principal. Like any other scientific theory, it may be initially be put forward for aesthetic or metaphysical reasons, but the real test is weather it makes predictions that agree with observation. This, however, is difficult to determine in the case of quantum gravity, for two reasons. First, as will be explained in the next chapter, we are not yet sure exactly which theory successfully combines general relativity and quantum mechanics, though we know quite a bit about the form such a theory must have. Second, any model that described the whole universe in detail would be much too complicated mathematically for us to calculate exact predictions. One therefore has to make simplifying assumptions and approximations – and even then, the problem of extracting predictions remains a formidable one.”
… Here Hawking, one of the most brilliant theoretical physicists since Einstein, explains the most common problems with modeling in every profession. A model is only valuable because it makes predictions about the relationships one tries to capture. However, the accuracy of those predictions is usually restricted to the amount of detailed information one can encapsulate. Thus, like most other professions, a model is only as valuable as the amount of pertinent information it holds, and how detailed a calculation one is able to perform with that data.
To ground this back with architecture’s struggle with BIM, it appears that our bottleneck, like Hawking’s before us, is at the scale change. While Hawking considered the enormously large and the exceedingly small, many introductory design studios force the analysis of a building operating at three primary scales: the Civic, the Human, and the Material Scales. The Civic Scale (roughly 1/64” = 1’-0”) describes how a building relates to the city. By describing the building as a specialized unit in a much larger whole, the Civic scale makes the viewer consider the building as an element in a larger organism, environmental, social, and in the confluence of flows. At the smaller Human Scale (roughly 1/4” = 1’-0”) the building is seen as an environment for its inhabitants. By describing the way the composition shelters, divides, and controls its inhabitants, the Human Scale forces the viewer to consider how the building mediates flows, social situations, and ecological situations. Finally the smallest Material Scale (roughly 3”=1’-0”) describes how individual components of a building are pieced together to assemble the composition. At this scale the physical properties of the materials used overwhelms other consideration, and reflection is spent on gravity, mass, strength, bonding, overlap, and thickness. Any architectural modeling system billed as “all inclusive” should be judged not only on how well it operates at one of these scales, but at all of these scales, and how well it allows the designer to change between them.
With this knowledge it is time to finally return to the measured responses at this month’s New York AIA Technology Committee event. Each presenter made clear that their model was a deliverable – but that the scope and purpose of that model was made explicit well before the BIM was made. In this way, the model was a design project that echoed the larger job of delivering a high-quality, customized project. Importantly though, the BIM was not responsible for encapsulating all the design decisions, as it is frequently billed. Instead these databases were the site of calculation of only a few design variables, not all the considerations for the project, in the same way that different scale plans are the site of calculation for far different issues.
Thankfully, the design community doesn’t know the scope of all that it will need to design in the future, and these wise panelists avoided making statements that one tool or even one approach to design will be adequate. "Is the traditional method of practicing architecture dead?" was recast by the end of the evening to include all the systems of collage, bricolage, and extra-resourceful guerilla-design that will necessarily keep things new and changing for generations to come.