MIT this week plans to publish two papers detailing ways to simplify the 3D printing process by using open-source software that is more intuitive.
Using computer graphics models and simulations, 3D printers can already produce a wide variety of 3D objects, but the software used in the printers is slow and difficult to use. But as 3D printing technology becomes more mainstream, it will require less computationally complex algorithms, MIT researchers said.
On July 25, a team of researchers from the MIT Computer Science and Artificial Intelligence Lab (CSAIL) will release its papers at the SIGGRAPH computer graphics conference in Anaheim, Calif.
"Our goal is to make 3D printing much easier and less computationally complex," said Wojciech Matusik, an MIT associate professor, co-author of the papers and a leader of the Computer Graphics Group at CSAIL. "Ours is the first work that unifies design, development and implementation into one seamless process, making it possible to easily translate an object from a set of specifications into a fully operational 3D print."
3D printing poses enormous computational challenges to existing software, the researchers said. In order to fabricate complex surfaces containing bumps, color gradations and other intricacies, printing software must produce a high-resolution model of the object, with detailed information on each surface that is to be replicated. The computer models can often produce petabytes of data, which current programs have difficulty processing and storing.
Matusik and his MIT team developed OpenFab, a programmable "pipeline" architecture to deal with those problems. OpenFab was inspired by RenderMan, the software used to design computer-generated imagery commonly seen in movies. OpenFab allows for the production of complex structures with varying material properties.
To create intricate surface details and the composition of a 3D object, OpenFab uses "fablets", or programs written in a new programming language that allow users to modify the look and feel of an object easily and efficiently.
"Our software pipeline makes it easier to design and print new materials and to continuously vary the properties of the object you are designing," said Kiril Vidimce, lead author of one of the two papers and a PhD student at CSAIL. "In traditional manufacturing, most objects are composed of multiple parts made out of the same material. With OpenFab, the user can change the material consistency of an object, for example, designing the object to transition from stiff at one end to flexible and compressible at the other end."
Thanks to OpenFab's streaming architecture, data about the design of the 3D object is computed on demand and sent to the printer as it becomes available, with little start-up delay. So far, Matusik's research team has been able to replicate a wide array of objects using OpenFab, including an insect embedded in amber, a marble table and a squishy teddy bear.
This video from MIT shows how Spec2Fab can streamline the 3D printing process.
In order to create lifelike objects that are hard, soft, reflect light and conform to touch, users must currently specify the material composition of the object they wish to replicate. That's no easy task, as it's often easier to define the desired end-state of an object -- for example, saying that it needs to be soft -- than to determine which materials should be used to make it.
To simplify the process, Matusik and the other researchers developed a new methodology called Spec2Fab. Instead of requiring explicit design specifications for each region of a print, and testing every possible combination, Spec2Fab employs a "reducer tree" that breaks the object down into more manageable chunks. Spec2Fab's "tuner network" then uses the reducer tree to automatically determine the material composition of an object.
By combining existing computer graphics algorithms, Matusik's team has used Spec2Fab to create a multitude of 3D prints, creating optical effects like caustic images and objects with specific deformation and textural properties.
Three rhinos printed using the Spec2Fab methodology
"Spec2Fab is a small but powerful toolbox for building algorithms that can produce an endless array of complex, printable objects," said Desai Chen, a PhD student at CSAIL and lead author of one of the papers.