Interactive Global Illumination

Abstract

Figure 1: Scene with complete global illumination computed at 1 fps (640 × 480 on 16 dual-AthlonMP 1800+ PCs) while the book and glass ball are moved by a user. Note the changing soft shadows, the caustics from the glass ball, the reflections in the window, and especially the color bleeding effects on the walls due to indirect illumination. Interactive graphics has been limited to simple direct illumination that commonly results in an artificial appearance. A more realistic appearance by simulating global illumination effects has been too costly to compute at interactive rates. In this paper we describe a new Monte Carlo-based global illumination algorithm. It achieves performance of up to 10 frames per second while arbitrary changes to the scene may be applied interactively. The performance is obtained through the effective use of a fast, distributed ray-tracing engine as well as a new interleaved sampling technique for parallel Monte Carlo simulation. A new filtering step in combination with correlated sampling avoids the disturbing noise artifacts common to Monte Carlo methods. CR Categories: I.3.7 [Computer Graphics]: Three-Dimensional