On a mild Saturday in mid-September, I arrived at Bell Park, a concrete basketball court near the Central Park Pink Line station in Chicago’s North Lawndale neighborhood. Inside a chain-link fence strung with concertina wire, the TLC song “Waterfalls” pumped out of tripod-mounted JBL speakers as Miami-based, award-winning architectural designer Germane Barnes shot hoops with event organizers. Children painted furniture-scale wooden blocks and operated remote control cars as the smell of barbecue drifted through the air.
This 2021 Chicago Architecture Biennial event, as advertised, looked like a block party. But in addition to hosting a day of activities and performances, the 16,000-square-foot site was the test bed for Cover the Grid, a geometrically sophisticated architectural-scale ground mural designed by the Columbus, Ohio–based studio Outpost Office and painted by a GPS-guided robot in just five days.
Owned by the Westside Association for Community Action, the poured concrete pad has operated as a basketball court and playlot since the ’70s. The site is home to two of this year’s CAB installations. Complementing Cover the Grid is Block Party, a pink play structure with intertwining ladders and tunnels created by Barnes in collaboration with University of Colorado assistant professor Shawhin Roudbari and local nonprofit MAS Context.
The projects, says local designer Jose Montanez, are intended to animate the site and draw attention to a grassroots initiative to which he’s attached, Under the Grid. Run by artist Haman Cross III, Under the Grid aims to revitalize 15 blocks of Chicago Transit Authority–owned land running beneath the Pink Line of the city’s elevated train system.
From a technology standpoint, what’s perhaps most novel about Outpost Office’s submission— the studio’s most ambitious mural project to date, says principal and co-founder Erik Herrmann—is that the basketball court was painted by the robot on a paint budget of $3,200 with limited on-site supervision.
Turf Tank One, the robot’s moniker, is typically used for marking athletic fields. The lime-green machine, about the size of a bumper car, has a suite of preloaded templates that includes “everything from an Olympic-scale track-and-field layout to something as modest as bocce ball,” Herrmann says. However, Outpost Office found a way to hack the system, applying new parameters of length and direction to certain “geometric primitives,” such as parallel lines, in the robot’s software library to form more elaborate patterns.
The result is a monolithic yet spatially intricate pattern of rectangles, pie-sliced arcs, and circles that together describe a basketball court, foursquare areas, and hopscotch routes.
While, in theory, the robot can operate entirely autonomously, Herrmann and fellow studio co-founder and principal Ashley Bigham remained on site to monitor its progress. Unexpected drawing glitches, lost GPS signals, and the occasional need to refill paint called for human intervention, Bigham explains—though most of their time was spent chatting with curious passersby.
The mural's lively palette incorporates pink, lime green, black, white, and primaries similar to those found in Google branding. The paint, by Pioneer Athletics, is free of volatile organic compounds and designed to fade in four to six months as sun, wind, and rain erode its pigments.
In a biennial characterized by, above all, a large number of permanent installations designed to showcase possibilities for activating Chicago’s 10,000 vacant lots, the impermanence of the project may make it seem like an outlier. But its plan for extinction reflects the vision of CAB director David Brown who, Hermann says, “wanted the installations not to have the kind of difficult legacy that a lot of biennial projects have, where the project falls into disrepair over time, and where there's no kind of plan for its obsolescence or disassembly.”
The project’s interstitial quality also resonates with the outcomes of a community planning process that began in February 2020 with “The Urban Hack.” The daylong "hackathon" included more than 70 residents and social impact designers, along with organizations such as Freedom House, Open Architecture Chicago, the School of Architecture at the University of Illinois Chicago, and The Trust for Public Land.
Eventually, Montanez says, the lot may be resurfaced, and the area underneath the Pink Line may be brought to life in the manner of The 606 in Chicago or the Underline, a 10-mile linear trail beneath Miami’s Metrorail. But the community needs to trust that the planning process is legitimate for development efforts to move forward in earnest. In a way, Outpost Office’s mural is an affirming stepping stone toward the realization of the larger, more inclusive vision for the space.
“We have these meetings and we talk about these ideas and this is our life,” Montanez says. “But this isn’t everyone’s life and, at some point, people get a little tired of all the chit chat about ideas and visioning. Having these in-between activities and installations helps to clarify what we’re doing and assure people, ‘We're here and we are trying to do this. It’s not just a school experiment.’ ”
In addition to providing a lightweight, expedient way to activate the space, the use of the GPS-guided robot offers cost advantages. (Outpost Office first used the robot in "Drawing Fields," its winning proposal in the 2020 Ragdale Ring Competition.) Because the robot had the capacity to paint both hardscapes and softscapes, it could be applied at a second biennial site, the El Paseo Community Garden in Pilsen. There, a 19,000-square-foot temporary painting was paired with a commissioned, permanent cast-concrete structure, The Garden Table by the Rotterdam, Netherlands–based firm Studio Ossidiana.
Translating the design pattern to a robotic template required some fairly sophisticated software scripting. The duo used Grasshopper within Rhinoceros 3D’s CAD application to create custom templates and color charts. They then remapped these drawings to the Universal Transverse Mercator (UTM) coordinate system, which divides the world into 60 zones, each 6 degrees of longitude in width. Once synced, numerical entries had to be manually entered into the robot’s G-code (a common programming language for running CAD/CAM applications) to ensure the robot would follow the correct course and not run over and smear freshly sprayed paint.
After mapping the design route, Outpost Office connected the robot to a base port communicating with 27 satellites and started the painting sequence. Running by itself, the robot painted the expansive design to within a centimeter of accuracy. “This technology allows us to impact really large spaces on a very low budget,” Bigham says. “And that was important for this project—[to] have an impact at an architectural scale without building brand new buildings.”
One might wonder how complex Turf Tank One’s canvases could be. Could the robot be programmed to replicate a painting like the Sistine Chapel?
Not yet, the architects say. Turk Tank One is currently limited to simple shapes: circles, rectangles, and the like. But the studio envisions applications for the robot beyond site activations at exhibitions and competitions, including full-scale ground surveys of future building sites.
As a proof of concept on an agricultural research plot at The Ohio State University (where Herrmann and Bigham are both assistant professors of architecture at the Knowlton School), Outpost Office is currently using the robot to paint a prototype of the proposed floor layout of a multifamily home. Herrmann says the tradition of a “draftsperson delineating buildings in the dirt” has a long history in architecture, citing the work of archaeologists and architectural historians who speculate that ancient buildings, like the Pantheon, were drawn in the ground at a one-to-one scale.
“We’re interested in both those scenarios,” Bigham says. “Installations and exhibitions that activate, inhabit, and create excitement around a space; and projects that use the robot to project the future plans for building sites at a one-to-one scale.”
