A beam tracing method for interactive architectural acoustics

Abstract

A difficult challenge in geometrical acoustic modeling is computing propagation paths from sound sources to receivers fast enough for interactive applications. This paper describes a beam tracing method that enables interactive updates of propagation paths from a stationary source to a moving receiver in large building interiors. During a precomputation phase, convex polyhedral beams traced from the location of each sound source are stored in 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, the precomputed beam tree(s) are used to generate propagation paths from the source(s) to any receiver location at interactive rates. The key features of this beam tracing method are (1) it scales to support large building environments, (2) it models propagation due to edge 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. The method has been demonstrated to work effectively in interactive acoustic design and virtual walkthrough applications.

An efficient GPU-based time domain solver for the acoustic wave equation

“…Most present-day room acoustics software packages use geometric methods [19]. Recent work such as AD-FRUSTA [20], edgediffraction [21], beam tracing [22,23], are able to accelerate these methods using ray and volume tracing. There has also been work on accelerating geometric techniques on the GPU [24,25] …”

A forward-advancing wave expansion method for numerical solution of large-scale sound propagation problems

“…Similar to the ray tracing technique are the the beam tracing methods [12,13,20] obstructed by several surfaces [19]. As for ray tracing, diffraction contri bution modelling is a problem for beam tracing methods [20].…”

“…Moreover, im portant propagation paths may be missed by all samples. In order to minimise the likelihood of large errors, ray tracing systems often generate a large number of samples, which requires a large amount of com putation [19].…”

Virtual reality for architectural acoustics

“…The main reason is the fact that sound in the full audio range must be simulated for frequencies and wavelengths covering three orders of magnitude (from 20 Hz to 20 kHz). This might be the reason for the delayed implementation of physically based 3D audio real-time rendering engines for virtual environments (Savioja et al 1999;Funkhouser et al 2004;Lentz et al 2007;Schröder et al 2010;Schröder 2011).…”