While many advances have been made in 3D printing multiple materials, it has remained difficult for non-programmers to create objects made of many materials without a more user-friendly interface. Now, a team from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) introduces “Foundry,” a system for custom-designing a variety of 3D printed objects with multiple materials. “In traditional manufacturing, objects made of different materials are manufactured via separate processes and then assembled with an adhesive or another binding process,” says Ph.D. student Kiril Vidimče. “Even existing multi-material 3D printers have a similar workflow: parts are designed in traditional CAD [computer-aided-design] systems one at a time and then the print software allows the user to assign a single material to each part.” In contrast, Foundry allows users to vary the material properties at a very fine resolution that hasn’t been possible before. Users can preview their design in real-time, rather than having to wait until the final steps in the printing process to see what it will look like. The team designed and fabricated a ping-pong paddle, skis with retro-reflective surfaces, a helmet, and a bone that could someday be used for surgical planning.