BIM Symposium at the University of Minnesota

On Feb 1, the College of Architecture and Landscape Architecture at the University of Minnesota hosted a BIM Symposium under its "Continuing Professional Studies" program. The focus of the Symposium was on addressing the opportunities and challenges related to implementing BIM in the office, as well as the educational challenges presented by BIM in the design studio. I was invited to deliver the keynote address at the Symposium, and other featured speakers included representatives from the leading AEC firms of KieranTimberlake, NBBJ, and Mortenson Construction. The Symposium concluded with a panel discussion and Q/A session, in which the four presenters were joined by representatives from the local firms of Ellerbe Becket, BWBR Architects, and HGA. The Symposium was very well attended by local industry professionals, and the presentations, panel discussion, as well as the questions from the audience made for a very stimulating discussion. This month's issue of "Building the Future" captures the highlights of this Symposium and discusses some of the main issues that emerged.

Keynote Presentation

The main purpose of my opening presentation at the Symposium was to provide a broad overview of the "state of BIM" and set the stage for the subsequent presentations that focused on how BIM was being specifically implemented at individual firms. Accordingly, I discussed both the benefits of BIM that were being realized now by firms adopting it as well as the potential benefits of BIM that would be realized by the industry as a whole in the long term; the latest technological developments related to BIM; the current status of implementation across the industry spectrum—in architecture, engineering, construction, and facilities management; the technological challenges as well as the social and professional challenges involved in implementing BIM successfully; and some of the future trends and technologies in AEC technology that I anticipated.

Since one of the important objectives of the Symposium was to explore how architectural education should be adapted in a BIM environment, I also discussed some of the new opportunities that I envisioned, both for teaching as well as for academic research in architecture. My list of suggestions included de-emphasizing 2D CAD; introducing students first to non-BIM 3D applications like SketchUp and form•Z and then transitioning them to designing in BIM; working on multi-disciplinary collaborative projects using BIM with students from engineering and construction management; and making it a requirement to do analysis such as energy, cost, etc. using the BIM model. As far as academic research is concerned, the ability to work with BIM applications using APIs has opened a minefield of possibilities: analysis tools can be developed for varied aspects of building design (in addition to the common ones of energy and cost) including circulation, habitability, code-checking, daylighting, ventilation, egress, and even more "hard to quantify" aspects such as aesthestics, cultural fit, feng shui, and so on. It is a terrific opportunity for researchers to push the technological envelope and develop tools and concepts that can actually be translated into real tools that professionals can use. (For more on research, see the recent AECbytes article, Academic Research in Architectural Computing.)

Let's move on to look at how the leading AEC firms represented at the Symposium are implementing BIM, "straight from the horse's mouth," so to speak.

BIM at KieranTimberlake

The firm of KieranTimberlake Associates needs little introduction, being famous for its oft-quoted book "Refabricating Architecture," which discusses prefabrication as a new industrial revolution that has the potential to transform the way buildings are planned, designed, constructed, and operated. In an article on a conference in Norway last February (see Prefabrication of Timber Buildings based on Digital Models: A Perspective from Norway), I described a presentation from Chris MacNeal of KieranTimberlake who described the firm's extensive research and actual work in the areas of modularity, mass customization, and offsite construction for building components ranging from composite door panels and curtain walls to entire rooms. At that time, KieranTimberlake was using generic 3D modeling applications such as AutoCAD and Rhino for building its 3D models, but saw the need to eventually develop 3D models capturing real world material and property information for a more efficient and effective modular design and offsite fabrication process.

At the BIM Symposium in Minnesota, Marilia Rodrigues of KieranTimberlake Associates described how the firm was starting to use Autodesk Revit Building for this purpose. For their pilot project, they chose a house that was to be fabricated offsite and assembled on the site in four weeks (see Figure 1). Since the size of the project was small, it allowed them to focus on the details and make a good start towards determining the process and methodology they should follow for future projects. The main goal for this project was to coordinate construction and fabrication using BIM, and the procedure followed was to break down the model into different parts. They made intensive use of Revit's object-making interface, the Family Editor, to create their own detailed custom components for different parts of the building including floor panels, aluminum frames, exterior cladding, mechanical components, connectors, and so on (see Figure 2). In many instances, custom objects were assembled together to create larger object modules. So, for example, the floor panels were modeled like furniture, with every joist and duct for heating and cooling built in. Similarly, some of the modular rooms such as bathrooms and closets were modeled with all the associated components including walls, plumbing, ceilings, etc. This allowed KieranTimberlake to study how the different parts of the building would come together, explore different alternatives for the sequencing the building assembly on site, and predict the problems that could arise. Each component created in Revit had a lot of information about its physical properties built into it, creating a close-to-real-life simulation of the building. In some cases, Revit's advanced parametric capabilities were used to build physical limitations into components; for instance, the length of an aluminum frame could not exceed a specified value in reference to certain associated criteria.

KieranTimberlake has extended the use of the BIM model well beyond the design phase to the construction and fabrication phase. The scheduling capabilities of the application are being used to coordinate the construction process with the suppliers and contractors (see Figure 3). The model itself is being shared with the mechanical engineer for coordination and with the fabricators, who are using it to drive their manufacturing process, ensuring a closer fit between the design and the final building. This is all the more critical in a prefabricated building since any "fit" problem at any stage will be propagated down the sequencing chain with an increasingly larger margin of error. Anyone who has tried assembling a piece of furniture and made an error within the first few steps should know exactly what this means.

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KieranTimberlake exemplifies one critical lesson of BIM implementation: you should know what you want to get out of the model. Both the process as well as the methodology will be quite different depending upon the type of building and the type of construction, and firms need to take this account when planning their BIM implementations. Going by KieranTimberlake's experience with Revit, it seems that BIM's object-based approach is a natural fit for the modular approach for prefabricated architecture, and should make it a lot easier to construct custom prefabricated buildings that don't have the "cookie-cutter" uniformity and monotony which have given prefabrication a bad reputation in the past.

BIM at NBBJ

In contrast to KieranTimberlake which has just started with BIM, NBBJ is literally an old hand at this technology, having started with it 8 years ago using Bentley's MicroStation Triforma-based BIM applications (known at that time as object-based CAD). In his presentation at the BIM Symposium, Daniel Ayars of NBBJ highlighted that with offices in 7 different locations, including London and Shanghai, an integrated design approach comprising space, structure, mechanical systems, interiors, and lighting was critical to NBBJ, and BIM forms the centerpiece of this approach (see Figure 4). More recently, NBBJ is starting to push rapid prototyping as a means of generating the fabrication model from the BIM model. They are also focusing on building systems coordination using the integration capabilities of Bentley Architecture with Bentley Mechanical and Electrical Systems.

Figure 4. NBBJ sees BIM as the centerpiece of a collaborative design process that integrates all the different building-related disciplines. (Courtesy: NBBJ)

NBBJ's foray into BIM started in 1998 with the U.S. Federal Courthouse project in Seattle (see Figure 5). Even though Triforma was relatively immature at that time, NBBJ used it in the conceptual design phase for exploring different massing options, deriving the floor areas to verify them against the program requirements, and coordinating between the interior and exterior aspects of the design. Once the design was finalized, a comprehensive 3D model was developed which was used for generating all the visualizations as well as 2D extractions for the construction drawings. Many details, however, were shown only in 2D sectional drawings as to keep the model size within workable limits.

With each subsequent project, NBBJ has taken its use of BIM a little further. For example, in the 2003 Washington Mutual Center project located in Seattle, NBBJ started with a team that had a lot of experience in 3D, and they were able to integrate the architectural, structural, and mechanical models and detect conflicts (see Figure 6). However, the frustrating aspect of this project for NBBJ was that the consultants and contractors preferred to stick with the 2D approach, so all the multi-disciplinary model integration had to be carried out by NBBJ in-house.

In contrast, in a more recent project, Cleveland Clinic Hospital's Glickman Tower, NBBJ had their project consultants working in 3D as well, allowing their 3D models to be directly integrated into the design process. All model files, including those from the consultants, were referenced into one composite file from which extractions were made to generate 2D plans, sections, and elevations (see Figure 7). This same composite model was also used for generating interior and exterior renderings, all in Microstation.

Figure 7. NBBJ's use of BIM on the Cleveland Clinic Hospital's Glickman Tower. (Courtesy: NBBJ)

To date, NBBJ has done 35 to 40 projects using BIM, and is pushing it hard. Close to 3/4ths of the firm is now using BIM at various levels. Sometimes, Daniel Ayars acknowledged, BIM is pushed too hard and then it is not as successful. Looking ahead, the issues critical to NBBJ are multi-disciplinary collaboration, early participation in the process from contractors and fabricators, resolving the issue of model ownership, and determining the new business alliances in the new BIM-based project workflow. For BIM collaboration, NBBJ has implemented Bentley's ProjectWise, which allows the model to be located on a central server where all of NBBJ's offices can have access to it. The integration of different disciplinary models is getting better—so far, the process has been smoother with structural, but mechanical is catching up. NBBJ is still determining which is the best method of communicating changes between the consultants. To date, communication has been through the direct exchange of 3D models, but the firm is looking for new modes of communication made possible by the 3D process, including the use of Adobe's 3D PDF format.

BIM at Mortenson Construction

The contractor's perspective at the BIM Symposium was provided by Jim Yowan of Mortenson Construction, who described how they used 3D/4D technology in challenging projects such as the Walt Disney Concert Hall (designed by Frank Gehry) and the Denver Art Museum Expansion (designed by Daniel Libeskind). The Walt Disney Concert Hall in particular, which Mortenson worked on in the late 1990s, was a very difficult project, and Mortenson was literally forced into adopting 3D as they received primarily 3D models from the architect as the "contract documents." Moreover, these 3D models were in the form of 3D line wireframes, and Mortenson had to painstakingly convert each one of them into 3D geometric models. This was also true for surfaces; for example, for the auditorium ceiling, only a 3D CATIA surface model was provided and Mortenson had to use this for designing the actual ceiling panels in 3D using CATIA (see Figure 8). These 3D models also functioned as shop drawings for construction. The same was true for the ductwork above the ceiling, and other components of the building. Being a complex building to construct, the scheduling was critical and Mortenson collaborated with Stanford's CIFE and Walt Disney Imagineering to create a 4D model, integrating the time factor into the 3D model. Mortenson found 4D a very powerful communication tool and now routinely uses it on projects.

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For its more recent Denver Art Museum Expansion project, Mortenson embraced innovation and aggressively implemented 3D/4D without being forced into it as with the Disney Concert Hall project. What also helped in this case was the both the architect and the structural engineer (Ove Arup) were also using 3D for their respective tasks. Mortenson used both the architectural and structural models to create a detailed 3D construction model integrating all the main subsystems: the concrete model comprising foundations, basement, and core walls; the steel model comprising beams, columns, plates, and angles; the architectural model comprising the shell, interior walls, ceilings, soffits, doors, and windows; the mechanical system comprising ducts, VAV's, and shafts; the sanitary, water, and gas plumbing systems; the electrical system including light fixtures, conduit, and trays; the fire protection system including pipes, fittings, and heads; and other miscellaneous components. The detailed model helped in multi-disciplinary coordination and clash detection through the use of NavisWorks; it also allowed the complex details of the project to be better visualized in 3D (see Figure 9).

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For their more traditional projects, Mortenson still prefers to build a detailed 3D model of the kind shown in Figure 9 for better coordination, conflict detection, and scheduling, despite the fact that most architects continue to give them traditional 2D design documents. Using this technology, Mortenson has been able to completely eliminate clashes in their construction process. They see a model-based future for the industry where they assume most of the responsibility for the model during the construction process and use it to coordinate with fabricators and suppliers. They also see a great opportunity to extend their service to the owner beyond the construction phase and lead the facilities management and operations for the building. For Mortenson, technology is seen as the enabler of innovation and they are embracing it with open arms, making them one of only a handful of construction firms in the U.S. which is actively implementing BIM.

Panel Discussion and Conclusions

The individual presentations at the BIM Symposium were followed by a panel discussion in which the presenters were joined by representatives from local firms including BWBR Architects, HGA, and Ellerbe Becket, all of whom were either already implementing BIM or getting started with it. Most of the panel discussion was devoted to answering questions from the practitioners in the audience. The main issues discussed were related to billing, contracts, liabilities, and the risks involved in implementing BIM. One interesting question that was raised was related to billing: considering that most architects billed their clients by the hour rather than on a project basis, what were the cost benefits in eliminating non-value added activities using BIM? Needless to say, the architectural profession needs to find new ways of billing in order to get the most benefits from implementing BIM. Some audience members questioned the "cheaper, faster, and better" marketing rhetoric behind BIM and asked if this was really true. The answer to this from those panelists such as NBBJ, Mortenson, and HGA, who were ahead of the curve in BIM implementation was a resounding "yes." They all agreed that BIM makes for a better design process and product and also provides more business opportunities. And while BIM may be an optional technology at the moment, it won't stay that way for too long—some of the panelists revealed that they already had clients coming in asking for BIM.

It was generally agreed that BIM is going to bring about many changes in the architectural profession. It calls for new learning, the application of new processes, the development of new workflows, and better knowledge of other building disciplines. The position of draftsperson will certainly be eliminated. What is not clear is if it will be replaced by a new "modeler" position with the same disconnect between designer and modeler as there currently is between the draftsperson and the designer. This also relates to the question of how to best educate students for a professional future in which BIM will play an important role. How much of BIM should be taught in schools? Even with CAD, there was always the fear of "students getting lost in the computer," which made many studio instructors prohibit their students from using CAD on projects. Will this be the same with BIM? Or is BIM so fundamentally different from CAD that it could prove of tremendous value in core architectural education, in helping students understand how a building goes together? There are no pat answers to these questions. We can arrive at specific conclusions only after schools start experimenting with incorporating BIM in their curriculum. The University of Minnesota has recently made a start on this, and I will report on their experience in a future AECbytes article.

To sum up, the main points that emerged from the Symposium were that BIM is undoubtedly gaining momentum, and that there are lots of benefits to be gained from deploying it. BIM can be used to improve existing processes as well as explore new ways of design and construction such as custom prefabrication. The presenters warned, however, that the path is not easy and there is a learning curve involved. They also advised the audience to not get hung up on the technology and avoid a long-drawn out evaluation process to determine the "best BIM tool"—instead, they should just go ahead and get started. There might be no immediate returns on the investment, but it will open up lots of new business opportunities down the road, including post-construction facilities operations and maintenance.

The College of Architecture and Landscape Architecture at the University of Minnesota deserves to be commended for keeping up to date on the latest technology developments in the industry and bringing together leading AEC firms in such an informative and stimulating Symposium for the benefit of the local firms. If more universities around the world took similar initiatives, it would dramatically improve the state of the art in the building industry.

About the Author

Lachmi Khemlani is founder and editor of AECbytes. She has a Ph.D. in Architecture from UC Berkeley, specializing in intelligent building modeling, and consults and writes on AEC technology. She can be reached at lachmi@aecbytes.com.

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