Interactive Global Illumination for Improved Lighting Design Workflow

In this paper, we present a hybrid software–hardware rendering technique which can compute and visualize global illumination effects in dynamic scenes at interactive rates. Our system uses a hardware splatting technique simular to, but developed independently of, Stüerzlinger et al. The technique involves a progressively refined photon tracing calculation capable of simulating a wide range of BRDFs. Photons in the scene are rendered to the screen as oriented Gaussian splats. This compact representation allows for rapid rendering of scenes with thousands of photons on consumer-level hardware. In contrast to previous methods using simular techniques, our system does not use precomputed lighting, and is capable of achieving interactive feedback to object and light manipulations. Such a feature is invaluable to lighting designers dealing with complex globallyilluminated scenes. The progressive refinement algorithm allows for rapid preview during interaction, while producing higher quality images over time. The images produced also maintain a high correlation to the appearance of full renderings using a conventional Monte Carlo ray tracer.