We are working on technologies that enable the understanding and creating of items and systems that are difficult, if not impossible, to otherwise confront. One such technology that we developed is in essence the inverse of our previous expansion microscopy (ExM) invention. We call this technology implosion fabrication (ImpFab, for short). In ImpFab, we can directly assemble 3D nanomaterials consisting of metals, semiconductors, and biomolecules arranged in virtually any 3D geometry. We use hydrogels as scaffolds for volumetric deposition of materials at defined points in space. We then optically pattern these scaffolds in three dimensions, attaching one or more functional materials, and then shrink them in a controlled way to achieve nanoscale feature sizes in a solid substrate. Using ImpFab, we achieve resolutions in the tens of nanometers and complex, non–self-supporting 3D geometries of interest for optical metamaterials.