Additive manufacturing, otherwise known as 3D printing, has become an essential tool of manufacturing. The most prominent method for the creation of large-scale metallic parts is directed energy deposition (DED), in which lasers or other energy sources are used to melt a powder stream or wire feedstock to deposit the material layer by layer on the build platform. A team of scientists used hard X-ray techniques and multi-physics modeling to penetrate the process of a little-studied wire-laser DED technique.