A Framework for Global Dlumination in Animated Environments
Jeffry S. Nimeroff, Julie O'B. Dorsey, Holly Rushmeiei · 1995
We describe a new framework for efficiently computing and storing global illumination effects for complex, animated environments. The new framework allows the rapid generation of sequences representing any arbitrary path in a within an environment in which both the viewer and objects move. The global illu mination is stored as time sequences of range-images at base locations that span the view space. We present algorithms for determining locations for these base images and the time steps required to adequately capture the effects of object motion. We also present algorithms for computing the global illumination in the base images that exploit spatial and temporal coherence by considering direct and indirect illu mination separately. We discuss an initial implementation using the new framework. Results from our implementation demonstrate the efficient generation of multiple tours through a complex space and a tour of an environment in which objects move. In this paper, we present a range-image based approach to computing and storing the results of global illumination for an animated, complex environment. Range-image based systems have been used previously in flight simulators (3) and in computer graphics (7). Range-images store the distance to the visible object for each pixel, as well as the radiance. While previous research has demonstrated the potential of range-image systems to allow a user to tour a complex scene at interactive rates, the problem of efficiently rendering animated, globally illuminated environments within the context of such a system has not been considered. In this paper, we present a new framework that addresses this problem. The contributions of this paper are several. We build on previous work by considering how animated environments (i.e. environments in which objects as well as the user can move) can be represented as time sequences of range-images. We explore how to select a set of base views for the range-images as well as the time steps required to capture the effects of object motion. Further, we consider how global illumination can be efficiently computed to generate each of the range-images. Previous global illumination methods have