Towards a Materials-Based Building Information Model

A Revolution in Need of Traction

While the central ideas behind building information modeling (BIM) have been around for more than two decades, the paradigm-shifting concept that buildings should be designed and communicated via intelligent digital models—in lieu of paper drawings—has yet to establish a significant foothold in the mainstream of the building design professions. Commentators have attempted to diagnose the reasons behind this peculiar disconnect between the potential of the technology and its widespread adoption among architects and other building professionals. Most of them attribute this primarily to the reluctance of the design professions to replace their time-proven tools and production methods with disruptive new tools, whose profitable return on the significant investment they require has yet to be proven.

Yet, the fact that the aerospace and automotive industries, along with other product design industries, have essentially transformed their design and manufacturing processes to be centered on the development of intelligent digital models has been touted for several years now. Indeed, why can't we make buildings like Boeing makes airplanes? In a commentary on the subject, Ken Sanders, FAIA, presented a compelling description of how the building design and construction industry differs from the other product manufacturing industries. However, despite all of the differences between the nature of the products, between the economies of scale, and between the design, regulation and manufacturing processes, it remains that a building is essentially a product which, like all other products, must be designed, produced, maintained, and increasingly, recycled.

First Steps and New Tools

Integrating the design-build process in the AEC industry and developing new types of partnerships between the concerned parties—particularly owners, designers, builders and manufacturers—are unquestionably critical first steps. However, in pursuing these objectives, we should not cease to be vigilant in assessing the software tools that claim to facilitate the BIM paradigm shift. Could it be that yet more intelligent and knowledge-laden tools could hasten the organizational transformations necessary for a fully realized implementation of BIM?

It appears to me that if the building information model is to achieve its full potential as a design analysis and building lifecycle management tool, it must first be structured around the detailed representation of real materials as its fundamental building block. The concept of digitally representing material properties is, of course, not new. Other design industries regularly use product modeling packages such as Catia and ProE that link to computational fluid dynamics (CFD) and finite element analysis (FEA) type software. These tools can simulate material behavior and characteristics to a degree that practically obviates the need to build physical models for analytical purposes during product development.

Given the increasing accessibility of this type of analytical software—in terms of its user interface and the growing capabilities of computer hardware—and the rapidly-developing interest in digital modeling within the building and environmental design disciplines, perhaps it is time to aggressively exploit the logical co-dependencies between these kinds of tools.

What's Wrong with What We've Got?

My contention is that the current generation of BIM software falls short in the manner in which it facilitates most of the essential types of design simulations (i.e. structural, hydrological, thermal, fire and life safety, acoustical and lighting) that would enable thorough and reliable digital analyses of building performance. While lighting analysis software that works fluidly with geometric, light source, and material surface properties encoded within the building model is already in common use, integration of the data required for most of the other important types of simulations (with the possible exception of structural analysis) into the building model seems to be deficient. Contributing to this deficiency is the absence of widely accepted coding standards that could facilitate both incorporation of and open access to this data in the building model. Acknowledgement must be given, however, to the considerable effort that has been and is being put into developing building model information standards such as the Industry Foundation Classes (IFCs) and gbXML.

By way of example, one of the primary properties that should be readily and effortlessly extracted from the building model, in order to facilitate a thorough and detailed heat loss/gain analysis of a building envelope, is the U-factor for each of the components of the envelope. This property, combined with the relevant geometrical properties, as well as the external environmental conditions and loads under consideration, would theoretically provide the complete set of data necessary to undertake this type of analysis. Simulations of this type would be conducted iteratively throughout a structure's design, and would, in most cases, have some bearing on the development of the design. Upon completion of the building project, this thermal simulation could serve as a benchmark against which the thermal performance of the actual structure is measured.

Throughout the lifecycle of a structure built under this scenario, the building model could serve both as benchmark and testing ground for the thermal impact of potential alterations to the structure. The benefits of this approach to building design and management further reinforce the potential advantage of BIM over current methods of creating and updating archival records of building structures, otherwise known as "as-built" drawings.

However, in order for these benefits to be realized, the building model must be laden with, or intelligently linked to, material/product data with a level of comprehensiveness and detail that might be viewed by some as beyond the realm of practicality or reason. If real-world simulation is the consummate goal of building modeling, the digital counterparts to real-world objects must be developed to incorporate and encode more and more of their essential real-world properties. The actual U-value of a typical wall is dependent upon so many potentially unique conditions (e.g., size, shape, composition, connection details, number, size and types of openings, adjacencies, etc.) that deciding on the value for a wall instance within a model created with one of the current BIM packages could prove highly unreliable without an exhaustive accounting for all of those unique conditions or an extensive list of qualifications.

So why are building models not yet commonly used in a manner similar to that described above? While the reasons are manifold and complex, I believe that the state of popular BIM software tools is a primary reason. None of the available building software packages that aspire to BIM seem to adequately encode and process sufficiently focused and detailed physical properties of building materials and components within the building model in a manner that would facilitate detailed performance analyses by the typical building design team.

Materials as Foundation

The age-old question about what constitutes the alphabet of architecture might, in some sense, be satisfied if we consider the materials used for building construction as the most basic and readily definable components of the built environment. There are some salient points of correlation between the role of an alphabet in the construction of language and that of materials in the construction of built structures. Similar to the manner in which a relatively small number of alphabets are assembled into a variety of customary arrangements to produce units of meaning, a limited reservoir of natural or fabricated materials can be assembled in a great variety of configurations to produce built structures or the components thereof. As in written language, the basic components of built structures remain distinct and recognizable within the structures they form while contributing to functions and roles that depend intrinsically on their relationships with other neighboring components.

This analogy, if taken to an extreme, would, admittedly, encounter several limitations. It is, nevertheless, one that seems to fit on several important levels, including those described above. It is also what I perceive as a substantive void in today's building information modeling applications.

About the Author

Lloyd James, AIA (B.Arch Andrews University, M.Arch Univ. of Florida), is an Assistant Professor at Morgan State University's Institute of Architecture and Planning and a practicing architect with over 15 years experience with both large and small firms. He teaches courses in building materials, environmental systems, and communication skills, and conducts research on computer-aided design, technology, and practice. He can be reached via email at ljames@moac.morgan.edu.

Note: The views expressed in Viewpoint articles are those of the individual authors and do not necessarily reflect those of AECbytes. Also, no advertising or sponsorship is accepted for Viewpoint articles.

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