In 2016, the American Institute of Architects reported that BIM was used for nearly 100 percent of projects at large firms. But for landscape architects, BIM has traditionally fallen short, with professionals calling it clunky, building-centric and overly complex with too many limitations for landscape design.
Stories have popped up of landscape architects using BIM, by way of Revit, from start to finish for projects including drought-tolerant landscapes, rooftop and courtyard gardens and much more. Whereas most landscape architects compose their designs in a combination of plan views, sections, and 2-D details, and must create additional 3-D renderings for illustration purposes, with BIM, everything is modeled in 3-D from the start—a huge aid for envisioning how the design will translate from paper to a park or plaza. Every object in the design is linked to its own database, which might include information such as dimensions, weight, carbon footprint, and cost. As a result, chores such as material takeoffs and scheduling, not to mention revisions, are much easier.
BIM might be more time consuming up front than 2-D drafting, but as the project progresses, that initial investment more than pays for itself. “It is vastly more efficient,” says Meghen Quinn, Principal, RLA, ASLA, LEED AP, with Hargreaves Associates. “You design in 3-D, and then the program creates the 2-D construction documents more or less automatically. With a 2-D program like AutoCAD, you have to constantly export and import information to a program like SketchUp to do three-dimensional studies. You end up redrawing a lot of things, so it’s like you are doing it twice. In Revit, you just model it once, and then you can cut as many sections and elevations as you want, with basically the click of a button.”
Quinn has found she can co-opt the building-based tools of Revit for landscape purposes. The “floor” tool, she says, works just fine for designing the biofiltration planters that are a signature feature in her work. California regulations require on-site treatment of all stormwater on sites above a certain size, which, on tight sites, Quinn likes to take care of in raised beds that hold layers of gravel, engineered soil, mulch, reeds, and other water-loving plants. Different jurisdictions in the state have different requirements for the size of gravel, depth of mulch, and other parameters, which she can quickly alter in a Revit model to suit the circumstances.
“Architecturally, a floor assembly might include things like decking, joists, carpet, some kind of subfloor,” Quinn explains. “The floor feature that comes out of the box with Revit allows you to have all those layers, each with its own dimensions and materiality, and gives you the ability to apply rendering treatments to them. It’s perfect for biofiltration planters—you might have three inches of mulch over 18 inches of soil mix over 12 inches of drain rock, and you can use the floor tool to make those layers. Then you just draw the planter, set the elevations that you want the top of your soil to be, and the program turns it into a 3-D model.”
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BIM is most applicable, and easiest to adapt, on landscape projects that are highly integrated with a building, Quinn says. Laying out the hills, dales, and undulating pathways of a park are trickier, but not impossible. Revit’s three-dimensional surface modeling tools are quite elementary, so she recommends modeling complex, organically shaped features in Rhino, a program with files that are readily imported into Revit models.
Another huge plus: BIM software is also typically cloud-based, allowing all members of a design team to work from a single model that updates in real time, which often means faster, stronger communication and collaboration with architects, structural engineers and others.
April Is World Landscape Architecture Month. You can share your favorite landscape architect-designed space all month on social media using the hashtag #WLAM2019.