Refining multi-material 3D printing at MIT

OpenFab rhinos

“3D printing hardware is rapidly scaling up to output continuous mixtures of multiple materials at increasing resolution over ever larger print volumes.” That’s the first sentence of the abstract for a paper called OpenFab: A Programmable Pipeline for Multi-Material Fabrication. A high-resolution digital object that’s made up of multiple materials can be comprised of trillions of voxels and require petabytes of storage capacity. Such objects are computational hurdles, even with the advent of cloud computing. Additionally, 3D printing software is designed to process polygon meshes, which makes gradients of multiple materials difficult to apply.

To address this issue a team at the Computer Science and Artificial Intelligence Laboratory (CSAIL) of MIT created a program called OpenFab. If there’s a group that understands the burden of digital 3D objects it’s the people at Pixar. Their software called RenderMan is highly efficient with rendering scene geometry. As such, OpenFab is inspired by RenderMan. It operates as a pipeline, procedurally generating material composition and geometry and sending it directly to the printer; very little of the final volume is stored in memory.

OpenFab allows for the efficient creation of multi-material objects that possess more properties than materials by mixing the materials in various amounts. Another problem arises though. Specifying material composition for desired properties is incredibly difficult and tedious. So a team from the same lab created another interface called Spec2Fab to translate specification goals into material composition. Its “reducer-tuner model” goes a bit over my head, but the video offers a nice demonstration.

Wojciech Matusik, MIT associate professor, co-author of the papers, and a leader of the Computer Graphics Group at CSAIL states “Our goal is to make 3D printing much easier and less computationally complex. 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.” This research will ultimately lead to intuitive interfaces that allow operators to set hardness, transparency, texture, and flexibility with simple inputs such as sliders; the program will calculate the specific material composition. Go MIT!

Source: Computerworld