Researchers in MIT’s Media Lab, Cambridge, MA, have created “Cilllia,” a new computational method for designing and 3D printing artificial hair. 3D printers have been unable to print hair, fur, and other dense arrays of extremely fine features that require a huge amount of computational time and power.

The researchers found a way to bypass a major design step in 3D printing to quickly and efficiently model and print thousands of hair-like structures. Instead of using conventional computer-aided design (CAD) software to draw thousands of individual hairs on a computer — a step that would take hours to compute — the team built a new software platform that lets users define the angle, thickness, density, and height of thousands of hairs in just a few minutes.

Using the new software, the researchers designed arrays of hair-like structures with a resolution of 50 microns, which is about the width of a human hair. Playing with various dimensions, they designed and then printed arrays ranging from coarse bristles to fine fur, onto flat and also curved surfaces, using a conventional 3D printer.

The team is investigating how 3D-printed hair could perform useful tasks such as sensing, adhesion, and actuation. To demonstrate adhesion, the team printed arrays that act as Velcro-like bristle pads. Depending on the angle of the bristles, the pads can stick to each other with varying forces. For sensing, the researchers printed a small furry rabbit figure equipped with LED lights that light up when a person strokes the rabbit in certain directions. Finally, to see whether 3D-printed hair can help actuate, or move objects, the team fabricated a weight-sorting table made from panels of printed hair with specified angles and heights. As a small vibration source shook the panels, the hairs were able to move coins across the table, sorting them based on the coins’ weight and the vibration frequency.

The ability to fabricate customized hair-like structures not only expands the library of 3D-printable shapes, but it also enables users to design and quickly prototype components such as passive actuators and swipe sensors for use in everyday interactive objects.