Full Wave Modelling of Light Propagation and Reflection

The propagation and reflection of electromagnetic waves in a three-dimensional environment is simulated, and realistic images are produced using the resulting light distributions and reflectance functions. A finite difference time domain method is employed to advance the electric and magnetic fields in a scene. Surfaces containing wavelength scaled structures are created, the interaction of the electromagnetic waves with these nano-structured materials is calculated, and the sub-surface interference and diffraction effects are modeled. The result is a reflectance function with wavelength composition and spatial distribution properties that could not have been predicted using classic computer graphic ray tracing approaches. The techniques are employed to reproduce demonstrations of simple interference and diffraction effects, and to create computer-generated pictures of a Morpho butterfly.