In computer graphics, modeling light scattering from objects is important for computing realistic images. Most scattering models for surfaces and fibers that are used in graphics are based on ray optics, with some surface reflection models based on approximate scalar diffraction models. I'll talk about some recent projects from my group that have applied more accurate full wave simulations to predict detailed scattering from fibers and surfaces in order to learn what is being missed by these simplified models. For fibers, we've found that diffraction is an important scattering mode that was neglected in previous models and that optical speckle produces color glints that contribute to highlight appearance. For surfaces, we find that for less rough surfaces, scalar diffraction theories match the exact simulations well, but for surfaces with high roughness and more organized structure, the full simulation is needed for accurate predictions. I'll also discuss how these results can inform better models for production rendering.