Computational Visualization of Semi-transparent Metallic Thin Films with Roughness

We model the visual appearance of thin, semi-transparent metallic films coated on arbitrary three-dimensional substrates, incorporating effects including nanoscale film roughness, microscale substrate roughness, and source of light. Film reflectance is modeled by combining electrodynamic simulations with a modified version of the Schlick approximation, which is adapted and validated to describe the color appearance of thin semi-transparent metallic films with nanoscale, subwavelength roughness. Diffuse scattering originating from microscale roughness of the substrate and partial reflectance is described by a microfacet model. Photorealistic rendered images generated by our approach are qualitatively compared to photographs of fabricated thin film samples under similar lighting conditions. We render images of semi-transparent metallic films as a function of film thickness, multilayer composition, substrate type, nanoscale film roughness, microscale substrate roughness, and environmental lighting, yielding physically plausible results consistent with previously reported observations.