The Lowly Folding Chair, Reimagined With Algorithms

The Swish stool is an example of using parametric design to kinetic effect.

At a glance, the Swish resembles nothing more than a fancy folding chair---a glamorous, indoor version of a canvas camping stool. See it in motion, though, and you’ll notice that the Swish chair looks unusually beautiful as it goes from a flat, folded position to an open, seated stance. The wood stool kind of twirls open, as if doing a cartwheel.

The Swish chair's 27 cherry wood pieces interlock with a series of hinges. Those hinges all conform to a slightly different shape. If Carlo Ratti, the director of MIT’s Senseable City Lab, had designed each hinge by hand, building Swish for Italian furniture company Cassina would have been a painstakingly slow process. But he didn't: Ratti let algorithms determine the form of each hinge. “That allows you to create shapes and functions that you otherwise wouldn’t be able to do,” he says. "When you can control the material in a much more dynamic way, then you can create objects that are quite magical.”

Carlo Ratti Associati

Algorithms have helped shape motorcycle parts, bridges, and even concert halls, but Swish is a new example of using parametric design to kinetic effect. Ratti built the chair by feeding a series of inputs into modeling software, a furniture-making technique he calls “programmable wood". The stool needed to fit certain weight and height requirements, and to stand in a more unique configuration than an average folding chair. It also had to be comfortable, so Ratti designed the seat shape around a 3-D scan of a human body. With those requirements in place, algorithms were able to spit out design suggestions until Ratti picked the one he wanted to CNC-mill into reality.

The Swish stool is still a prototype, but it's already noteworthy for how normal it looks---at least compared to other algorithmic designs. Last year, when Autodesk designers used algorithms to build the Elbo chair, the result looked skeletal, biological. This often happens when you let algorithms optimize the shape of the legs and back of a chair; they start to resemble animal bones, which have adapted over millions of years to carry loads stably and efficiently. The Swish stool, in contrast, looks less anatomical, less ornate. “Many people today are using parametricism to lead to some kind of baroque structure,” Ratti says. “We’re not interested in that.”

With Swish's sleek, sculptural looks, Ratti says he's exploring an aesthetic he calls digital minimal. It would seem at home in a modern apartment, and could still conveniently tuck away in a closet. That was Ratti’s goal: “The idea is to reinvent the folding chair,” he says. He's done that, along with reinventing---or at least, seriously rethinking---how to do it too.