Extremely small structures, far smaller in diameter than a strand of hair, could greatly benefit sensors and other devices. To master these nanomaterials, scientists need to determine their shape. That’s difficult. Scientists developed a new way to perform high-resolution, 3-D imaging of tiny metallic structures. The method uses scanning transmission electron microscopy (STEM). Using this method, scientists measured the 3-D structure of tiny gold stars, “nanostars.” Combined with computer simulations, the new method accurately predicted the physical and optical properties when compared with experiment.