Ronald Rael and Virginia San Fratello, principals of the Oakland firm Rael San Fratello, have been pushing the envelope on 3D printing in architecture. The duo—who started the spin-off company Emerging Objects in order to develop materials and applications for the technology—have built a talent for transforming low-cost waste materials into building components. Examples include outdoor furniture made from recycled tires, a casserole dish printed from curry powder, and a cabin built using 4,500 3D printed ceramic tiles. 

Beyond proving the potential of additive manufacturing, the two have helped to democratize the technology by making "3-D printing cheaper and more accessible," Patricia Leigh Brown explains in the New York Times. Mr. Rael and Ms. San Fratello often rely on the widely used method called "binder jetting," a process for which the standard materials can often be quite costly. In their pioneering use of non-traditional materials, from clay and wood to salt and chocolate, their work has become the proving grounds from which to show 3D printing as durable, affordable, and ecological.