A difficult challenge in geometrical acoustic modeling is computing propagation paths from sound sources to receivers fast enough for interactive applications. We paper describe a beam tracing method that enables interactive updates of propagation paths from a stationary source to a moving receiver. During a precomputation phase, we trace convex polyhedral beams from the location of each sound source, constructing a beam tree representing the regions of space reachable by potential sequences of transmissions, diffractions, and specular reflections at surfaces of a 3D polygonal model. Then, during an interactive phase, we use the precomputed beam trees to generate propagation paths from the source(s) to any receiver location at interactive rates. The key features of our beam tracing method are: 1) it scales to support large architectural environments, 2) it models propagation due to wedge diffraction, 3) it finds all propagation paths up to a given termination criterion without exhaustive search or risk of under-sampling, and 4) it updates propagation paths at interactive rates. We demonstrate use of this method for interactive acoustic design of architectural environments.

@article{Funkhouser:2004:ABT,
   author = "Thomas Funkhouser and Nicolas Tsingos and Ingrid Carlbom and Gary Elko
      and Mohan Sondhi and James E. West and Gopal Pingali and Patrick
      Min and Addy Ngan",
   title = "A Beam Tracing Method for Interactive Architectural Acoustics",
   journal = "Journal of the Acoustical Society of America",
   year = "2004",
   month = feb,
   volume = "115",
   number = "2",
   pages = "739--756"
}