The Internet was abuzz last week about a new idea, intriguingly dubbed “4-D printing,” emanating from the TED conference in Long Beach, California. Much of the buzz was probably a response to the sci-fi sounding name, which seems to imply that 3-D printing—itself all the rage right now—has already been supplanted as the technology most likely to take manufacturing to the next level.

In fact, the new technique still uses 3-D printing, or depositing materials layer by layer to build a custom 3-D structure. 4-D just involves using materials that help the new structure continue to assemble after it’s been printed.

Which brings us to the video that’s been making the rounds:

I spoke to Skylar Tibbits, a member of MIT’s architecture faculty and the brains behind the video and the concept of 4-D printing, and he explained what’s going on. The small white sections, Tibbits says, are made of a proprietary material developed by Stratasys, a leading manufacturer of 3-D printers. The material, which expands to 150 times its volume when placed in water, can allow a structure to self-assemble, to some degree, after printing. It is now part of a diverse arsenal of materials printable by a line of Stratasys machines called Objet Connex. The black material is rigid, serving to constrain the shape of the object, and could be substituted for a range of different substances, from hard plastic to soft rubber.
Tibbits and colleagues used newly developed software from Autodesk to determine the exact ratio and orientation of the two materials that would “program” the system to fold into a precise arrangement when placed in water. The proof-of-concept, says Tibbits, represents “a new paradigm for the way we make things.”

In principle these things don’t necessarily have to be water-activated, says Tibbits. “I’m hoping that in the future, with Stratasys, we could develop a whole line of these materials,” which could be activated by heat, water, sound, light, or pressure.

Thought-provoking stuff, but how might we see it used? Tibbits suggests that the technique could lead to adaptable water storage systems, or pipes that could adapt to changes in the environment or to fluctuations in demand. Maybe they would expand or contract to change capacity or flow rate, or undulate to move water along. “So the pipe itself is programmable and adaptable,” he says.

Even then, the potential would be limited until the new water-activated material could revert back to its original form if necessary. “We’re working to try to get a reversible version soon,” says Tibbits.