Beam Tracing with Refraction

This paper presents the beam tracing with refraction method, developed to examine the possibil-
ity of creating the beam tracing simulation of sound propagation in environments with piecewise non-
homogenous media. The beam tracing with refraction method (BTR) is developed as an adaptive beam
tracing method that simulates not only the reflection but also the refraction of sound. The scattering and
the diffraction of sound are not simulated. The BTR employs 2D and 3D topology in order to efficiently
simulate scenes containing non-convex media. After the beam tracing is done all beams are stored in a
beam tree and kept in the computer memory. The level of sound intensity at the beginning of each beam
is also memorized. This beam data structure enables fast recalculation of results for stationary source
and geometry. The BTR was compared with two commercial ray tracing simulations, to check the speed
of BTR algorithms. This comparison demonstrated that the BTR has a performance similar to state-of-
the-art room-acoustics simulations. To check the ability to simulate refraction, the BTR was compared
with a commercial Finite Elements Method (FEM) simulation. In this comparison the BTR simulated
the focusing of the ultrasound with an acoustic lens, with good accuracy and excellent performance.