Researchers have developed a new method for 3D printing objects with very different properties, including levels of hardness and transparency, on a pixel-by-pixel basis while using commonly available materials and inexpensive 3D printers. The method, described in the journal Science by researchers from The University of Texas at Austin, Sandia National Laboratories and two other national laboratories, could lend itself to the creation of realistic models of body parts for medical students to practice surgery on or new types of personal protective gear.