Durotaxis rocker features gradient mesh informed by function, ergonomics, and aesthetics.For Synthesis Design + Architecture founding principal Alvin Huang, there is a lot to love about 3D printing. But he does not always like how the technology is applied. "I see it all the time—a lot of students just 3D print everything," said Huang, who also teaches at the USC School of Architecture. "You see things that could have been done better, faster, or cleaner by hand. I find it a very troublesome predicament we're in, we're letting the tool dictate." When Stratasys contacted Synthesis about designing a piece for their Objet500 Connex3 printer, the architects decided to turn the relationship between human and machine on its head. Instead of asking how they could implement a preconceived design using the Objet printer, they challenged themselves to create something that could only be manufactured using this particular tool. Durotaxis Chair, a prototype of which debuted at the ACADIA 2014 conference, showcases Objet's multi-material 3D printing capabilities with a gradient mesh that visually communicates the rocker's function and ergonomics. Though Synthesis designed the Durotaxis Chair almost entirely in the digital realm, said Huang, "we see the computer very much as an intuitive tool, the same way previous generations thought of the pencil. We try to find a happy medium between the scientific aspect, and the intuitive manipulation of that science." The architects bounced among multiple software programs including Rhino, Grasshopper, Weaverbird, ZBrush, and Maya to craft a form that operates in two positions: upright, as a traditional rocking chair, and horizontally, as a lounger. The chair's structure comprises an interwoven mesh of two materials, one rigid, opaque, and cyan in color, the other flexible, translucent, and white. While the resultant gradients reflect both the physics and ergonomics of the chair, they also deliver an intended aesthetic effect, creating a moiré pattern that encourages the observer to move around the chair. "It wasn't the case of the code creating the form," explained Huang. "We very clearly sculpted it for visual and ergonomic properties." Stratasys manufactured the half-scale prototype at their headquarters in Israel. Unlike a typical 3D printer, which has one head with one nozzle, the Object contains two heads with 96 nozzles each. Using proprietary substances the company calls "digital material," said Huang, "you can print a matrix of gradients between those two heads. In our case, we were able to create gradients not just of color, but also stiffness and transparency." Synthesis remained in constant touch with the Stratasys team throughout fabrication, fine-tuning the design as problems arose. "It was also an experimental process for them," said Huang. "Ultimately, through a lot of back and forth, we were able to arrive at something they were able to print." Synthesis is now tweaking their design for a full-scale version of Durotaxis Chair. The principal challenge they encountered while fabricating the prototype, explained Huang, was an excess of support mesh. "It's still a big manual process. You have to remove all of the support material." The updated design will take advantage of the team's finding that, by printing vertically up to a certain angle, they can eliminate the need for support mesh. "We're trying to take it a step further," said Huang. "How do we expedite the process, and refine the geometry of the lattice so that you're changing direction before the material starts to droop? We're trying to do something where, in a sense, we're growing the chair." Despite his discontent with the way some young practitioners approach 3D printing, Huang thinks that the technology holds great promise, especially in the world of architecture. He points to some of his contemporaries, like fellow Angeleno and architect/jewelry designer Jenny Wu, who is taking 3D printing in exciting new directions. "When you think about architecture and design, most of what we do is the assembly of products, and the more bespoke you can make them, the better," said Huang. "I look at 3D printing as a shift from rapid prototyping to rapid manufacturing. Hopefully someday we can produce bespoke items for the same impact as mass-produced items—that is the theoretical holy grail."