Increased photorealism for interactive architectural walkthroughs

This paper presents a new method for interactive rendering of globally illuminated static scenes. Global illumination is decomposed into view-independent (diffuse) and view-dependent (non-diffuse) components. The two are recombined during rendering using a hybrid geometry- and image-based approach along with multi-pass blending techniques. This approach allows the preprocessing of both components and the fast rendering of globally illuminated scenes. The view-independent component uses a traditional precomputed geometry-based radiosity solution that is rendered using standard graphics hardware. The view-dependent component is decomposed into “what is reflected ” (radiance with depth) and “how it is reflected ” (BRDF), and precomputed and rendered using image-based approaches. Radiance is stored as images with depth, and rendered using perspective reprojection; the BRDF is decomposed into an integration of incoming radiance and a directional modulation. The radiance integration term is approximated by convolving the reflected image with precomputed kernel textures based on material properties. The directional modulation is stored as a reflectance modulation texture based on material properties and is rendered using spheremapping during a blending pass.