Interactive acoustic modeling of complex environments
Thomas A. Funkhouser, Ingrid Carlbom, Gary W. Elko, Gopal Sarma Pingali, Mohan Sondhi, James Edward West · The Journal of the Acoustical Society of America · 1999
A primary challenge in acoustic modeling is computation of reverberation paths from sound sources fast enough for real-time auralization. This talk describes a system that uses precomputed spatial subdivision and ‘‘beam tree’’ data structures to enable real-time acoustic modeling and auralization in interactive virtual environments. The spatial subdivision is a partition of 3-D space into convex polyhedral regions (cells) represented as a cell adjacency graph. A beam-tracing algorithm recursively traces pyramidal beams through the spatial subdivision to construct a beam tree data structure representing the regions of space reachable by each potential sequence of transmission and specular reflection events at cell boundaries. From these precomputed data structures, high-order specular reflection and transmission paths can be computed at interactive rates to spatialize fixed sound sources in real-time as the user moves through a virtual environment. Unlike previous acoustic modeling work, this beam-tracing method: (1) supports evaluation of reverberation paths at interactive rates, (2) scales to compute high-order reflections and large environments, and (3) extends naturally to compute paths of diffraction and diffuse reflection efficiently. A system based on this method is being used to develop interactive applications in which a user experiences a virtual environment immersively via simultaneous auralization and visualization.