Scientists working at microscopic scales have relied on a single dominant fabrication technique to build complex 3D structures. Their new approach enables micro- and nanoscale 3D fabrication using a wide range of materials, moving beyond polymers and opening new design possibilities. Researchers suspend microscopic particles in a fluid and focus a femtosecond laser on a precise point. After assembly, researchers remove the polymer mold in a post-processing step. Schematic illustration of the optofluidic 3D micro- and nanofabrication process.