The Limits of BIM

Landscape architects feel the push of architecture-centric software.

By Brian Barth 

Building information modeling, or BIM, has become the default digital format for designing buildings, bridges, and other infrastructure the world over, though in theory it is just as applicable to landscape design. You are not likely to find an architecture or engineering firm that does not employ BIM software, but there are surprisingly few landscape architecture firms that do. It’s not that landscape architects don’t appreciate the information-rich approach of BIM—quite the contrary—but many loathe its building-centric nature.

“Landscape architecture as a profession is kind of down on BIM,” says James Sipes, a landscape architect based in Atlanta who was an early proponent of adapting the technology for landscape architecture purposes. “It seemed to be exactly what we were looking for—that combination of CAD and 3-D modeling and smart software that linked things together in the way we as landscape architects design.” But, Sipes says, companies like Autodesk, which publishes Revit, a BIM software used widely by architects, “put a lot of time and energy into building BIM data for buildings and building components, but none of that had anything to do with landscape architecture.”

All of which would be fine if landscape architects weren’t being pulled into using the technology ahead of its time. In essence, BIM is a platform for coordinating design, budgeting, construction, and management activities. Consultants, contractors, and site managers share a centralized database with the client in which each component—a window, brick wall, water fountain, tree, and so on—has a wealth of information attached to it. Almost any sort of data relevant to a given component can be included, such as weight, dimensions, carbon sequestration capacity, or the website of the manufacturer.

The part that really gives designers goosebumps, however, is how these data sets interact. Advanced BIM software can spit out a custom report detailing the embodied energy of a particular facade treatment, the cost to build and maintain it over the life span of the building, and how much solar gain it has with a given orientation. Rotate the building pad 16 degrees east, increase the window openings 12 percent, press enter, and you’ll have a new report with all the updated values for the requested criteria. A few more clicks and you can export a plan, section view, and 3-D model of each scenario. If landscape architects have any strong feelings about BIM, envy may be among them.

“The beauty of BIM is that you can focus on the design and let the computer generate the construction documents…they become a by-product of the design process,” says Mark Lindhult, FASLA, the director of the MLA program at the University of Massachusetts Amherst. “That’s the ideal working methodology.” But BIM is of little help, Lindhult says, without “intuitive tools that landscape architects can adapt and apply to design.”

In 2007, Lindhult and Sipes approached Autodesk with a proposal to tailor BIM software to landscape architecture purposes, code-named Project Olmsted. The primary problem, they explained to a seemingly receptive audience of Autodesk executives, is that Revit, as well as its competitors, gets clunky once you leave the rectilinear confines of a building envelope. Sculpting topography, laying out curvilinear retaining walls, and designing other common components of a landscape architect’s repertoire on a BIM platform is no fun, Sipes says. “It will make you pull your hair out.” Getting from BIM to what Sipes, Lindhult, and others refer to as SIM (site information modeling) or LIM (landscape information modeling) wouldn’t take much more than a few thoughtfully considered plug-ins, they suggested.

“It just didn’t happen,” Sipes says. “It’s not that it just didn’t happen well, or only parts of it happened. It just didn’t happen.”

Lindhult says that in retrospect he’s not surprised. “We are definitely toward the bottom of the food chain in terms of being the ones that drive decisions and improvements in software. I think they figured it wasn’t really going to grow a new market for them. So they kind of killed that piece.”

Autodesk may dominate the market for design software, but it is far from the only company offering a BIM platform. Vectorworks, a design software company owned by Nemetschek Group, is one of the few players in the BIM market to make a substantial move toward a landscape approach, with a software package called Landmark. Eric Gilbey, ASLA, a landscape industry specialist with Vectorworks, says the company has begun the process of data building to make LIM a reality with a library of plant and landscape forms that come prepopulated with information but can also be configured based on the needs of the designer.

“We want to make [BIM] work for landscape architects,” Gilbey says, though he emphasizes that BIM is not something you learn on the fly. Even with Landmark, he says, there is a big learning curve to overcome before integrating the software in day-to-day work flow. “It would be one thing if all you had to do is pick up the software and run with it. But you need training in order to be proficient,” he says.

Jeremiah Farmer, the CEO of Land F/X, which makes a landscape and irrigation design plug-in for AutoCAD, stresses that BIM is a process, not a particular brand of software, a point that, he says, design professionals of all kinds tend to forget, leading to a frustrated search for a “holy grail” BIM program. “BIM is not this incredible new technology that people can run out and buy, and install as easily as a phone app,” he says. “BIM is very much a DIY solution at this point, made up of a collection of different software and methodologies that can change from project to project.”

Land F/X is not marketed explicitly as BIM software, but as a landscape-centric BIM-enabling tool. The idea, Farmer says, is to link AutoCAD and SketchUp, “allowing the designer to fluidly move back and forth between 3-D visualization and construction documentation,” which he considers the crucial functionality for landscape architects to participate in multidisciplinary BIM projects.

In the United Kingdom, landscape architects will soon have no choice but to master at least the basics of BIM—if they want to bid on most large government contracts, that is. Beginning in 2016, the national government has mandated that all “centrally procured” government contracts use what they call BIM Level 2 as a project management platform. Henry Fenby-Taylor, a landscape architect and BIM designer with Colour Urban Design in Newcastle upon Tyne, explains that “centrally procured” contracts equate roughly with federal contracts in the United States, but in Britain, the central government also does procurement for some schools, housing projects, and other developments that would fall under local jurisdiction here. The definition for BIM Level 2 is a little fuzzier, he says, but it’s less focused on the 3-D modeling aspect of BIM and more on “client information requirements: It’s about how exactly are we going to deliver what is needed on a project.”

Fenby-Taylor says the government mandate has caught landscape architects in the United Kingdom off guard, and threatens to exclude them from arenas they are accustomed to working in—meaning architects and engineers, who already use BIM by default, will likely fill those roles on project teams. “The knee-jerk reaction was, ‘Okay, I’m going to go buy a copy of Revit.’ That’s understandable, but it is possible to run a BIM Level 2 project using the standard tools that you’ve always used. It’s just about managing how you share information.”

The Landscape Institute, the equivalent of the American Society of Landscape Architects in Britain, has appointed Fenby-Taylor to write a software-agnostic manual for landscape architects using BIM, titled BIM for Landscape (Taylor and Francis), which is due out in the spring of this year. The Landscape Institute is also amassing landscape-centric data that designers can plug into any type of BIM software. “They’re sending a standardized template to manufacturers and nurseries for them to put their data into, [which] eases the work flow of sharing information,” Fenby-Taylor says.

Regardless of mandates, there is still a risk of landscape architects’ being left behind by the design and construction industry, or at least poorly integrated with it, if they don’t jump on the BIM bandwagon. BIMForum, a nonprofit cosponsored by the Associated General Contractors of America and the American Institute of Architects, is pushing forward a set of industry standards for BIM in the United States. Each year the group publishes an updated Level of Development Specification, a 195-page book of standards aimed at getting the entire building industry aligned in regard to BIM. Notably, the 2015 version contains seven pages of information regarding site design, most of which pertains to civil engineers rather than to landscape architects.

Some landscape architects suggest that ASLA should help facilitate the process of bringing the profession into the BIM world, as the Landscape Institute has in the United Kingdom. “I think it is appropriate for ASLA to lead that discussion,” says Matthew Wilkins, Associate ASLA, a cochair of the Professional Practice Network for Digital Technology. “Having a unified group speak out as a whole is always better.”

Wilkins, who uses a BIM approach in his daily work flow as a senior designer and planner at KTU+A, based in San Diego, says the operability problems and a lack of data are ultimately not what’s keeping the profession away from BIM; rather, it’s the lack of a clear methodology for integrating with BIM work flows. “Architects have almost exclusively gone the Revit route, and civils usually go through [Autodesk’s AutoCAD] Civil 3D. And yet here we are in this arcane style of designing and document production. Between the two—civils and architects—which one do we end up going toward? Or will there be a tertiary type of platform created just for our industry? It almost seems like there needs to be.”

BIM models are increasingly cloud-based, which allows real-time collaboration within a team of consultants and mitigates potential design conflicts. If the civil engineer on a project needs to move a drain pipe six feet, all the members of the team instantly have access to the new alignment because they are literally working in the same model. If the landscape architect needs to adjust the tree spacing as a result so roots don’t get into the drain, it’s a breeze to do so, and the architect will immediately see how the new tree spacing affects viewsheds from the building.

About a year ago Eric Kramer, a principal at Reed Hilderbrand, was studying the contract for a new project with a large architecture firm when he noticed language that he was not previously familiar with. Kramer was used to working with architecture firms that work primarily in BIM, but normally firms provide 2-D CAD files for their subcontractors who do not work in BIM. This particular contract said if CAD files were required, the landscape architect must agree to hold the architect harmless in the event that there were an error in the files used to coordinate the site work. Because the BIM files would be electronically converted to CAD files and the architect would not be going back to “check the accuracy of every line,” says Kramer, “the files would be for reference only and used at our risk. Someone has to take that responsibility, and we were not willing for that to be us.”

After some negotiation, the architect agreed to provide the CAD files; Reed Hilderbrand could rely on them as they were used to without assuming liability for errors that occurred in translation. “I think we got away easy on this one, but I can see the problem being a real one in the future,” Kramer says. “We were direct to the owner. Had we been sub to the architect, we might not have had as much leverage to get out of it.”

The question is, what would happen if an architect provided poorly translated BIM files to a consulting landscape architect and serious errors occurred as a result? In a legal sense, says Barry LePatner, an attorney specializing in the construction industry, construction drawings, whether in physical or digital form, are contracts: “The standard AIA agreement says the contract documents for the project shall include, not only the contract itself between the parties, but the specifications, the design documents and conditions…they all become legal documents.” Had Reed Hilderbrand accepted the architect’s conditions, or had the project gone forward without a clear agreement on file translation, the subcontractor would likely be held liable for mistakes in its drawings, while the architect would rest easily knowing that its BIM files were solid.

Ideally, such issues are worked out at the RFP stage. If the client wants the project to run on BIM, LePatner says, “usually the RFP says, ‘to all qualified people who want to put in proposals: You will be required to show proficiency in BIM as a condition of doing this project.’” In other words, subcontractors who don’t use BIM need not apply. Not that that should give any comfort to landscape architects.

Kramer speculates that BIM compatibility may become more of an issue as BIM requirements become more common in contract language. “Maybe it hasn’t been an issue because other architecture firms haven’t caught up to the complexity of what they’re doing yet. They don’t even recognize that there might be translation problems.“ He mentions, however, that some of Reed Hilderbrand’s institutional clients, including Duke University, now include wording in their standard contract for design services that requires the use of BIM. So far, the firm has been successful in negotiating exceptions to those terms. “But if more and more clients are going to be pushing that, it will be interesting to see what it forces landscape architects to do.”

Improving collaboration across disciplines is a central premise of BIM, but Autodesk’s near-monopoly on the software is a roadblock for landscape architects seeking to get on board. Many landscape architects would choose other BIM platforms that have more to offer in a landscape context, but compatibility issues between file types is a barrier on projects where architects or civil engineers act as the project prime. “In terms of interdisciplinary collaboration, there needs to be a tighter integration of data formatting to make the translation between one application and another,” Lindhult says. “Whenever you start translating, that always leads to unforeseen problems. Every new [software] version has some little tweak in terms of the data format, so there are always compatibility issues.”

Given the relatively small share of the design and construction market that belongs to landscape architects, the profession may have no choice but to cobble software solutions together as necessary—landscape architects are generalists, after all. Even if BIM eventually grows to a fully interdisciplinary SIM, the immense complexity of landscapes makes it difficult to plug every last component into a digital model. Much of BIM data for architects comes from the manufacturers whose products they specify. That approach to data collection fits with landscape architecture practice to a degree, but landscapes are much more than a kit of parts. Soil types, wildlife movements, and patterns of natural vegetation don’t come with a part number, but they remain central forces in the thought process behind any landscape design.

Brian Barth is a Toronto-based writer with a background in environmental planning and landscape design.

8 thoughts on “The Limits of BIM”

  1. Many architects here in the UK are multi-disciplinary offices and offer landscape design too, as we do ourselves. We use Revit for architectural BIM and have to model the site, trees, walls, fences, street furniture etc anyway (not least for visuals, but also for coordination) and therefore we use Revit to do the hard and soft landscape design too. This is a real hack, because Autodesk have ignored landscape design entirely, but we follow some of the methods outlined over at LandArchBIM and we get by…

    The future for us is Revit plug-ins, but none of these are mature yet.

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