CAD files do have some limitations and it takes hours of time and hard work to generate designs of hair as each strand has to be worked upon separately. Jifei Ou, an MIT graduate student in media arts and sciences stated that ‘hair’ has always been a difficult area to work on in 3D printing, because of software issues, as it was a lengthy and cumbersome process.
But MIT Media Lab has created a software program called Cillia that uses sliders to create thousands of hair with a density of 50 microns, on a particular surface. These sliders have various parameters where the length, density and texture of the hair can be adjusted as per requirements, with real-time visual representation. The quantity of hair and its shape can also be customised to generate interesting shapes like curls and spirals.
Hence, brush structures in various shapes and sizes can be created using 3d printing stereolithography. The team experimented by making Velcro-pads, paint brushes, furred toys that light up on stroking them, actuators, and more. All these take minimal time to design and create as each strand of hair does not need to be constructed individually.
This industry of 3D printing could touch $20billion by 2019, as per the reports of Canalys.
As per the paper presented by the Team at the Association for Computing Machinery’s CHI Conference on Human Factors in Computing Systems in May, it stated that the fabrication of the hair-like structures not only expands horizons in 3D printing technology but also gives them the opportunity to design actuators and sensors. It further stated that the 3D printed hair could be used in a technology to design day to day interactive objects.

Source: cnet.com