Fast Tracing of Acoustic Beams and Paths through Visibility Lookup

The beam tracing method can be used for the fast tracing of a large number of acoustic paths through a direct lookup of a special tree-like data structure (beam tree) that describes the iterated visibility information from one specific position. This structure describes the branching of bundles of rays (beams) as they encounter reflectors in their paths. For this reason, beam tracing is suitable for real-time acoustic rendering even when the receiver is moving. In this paper, we propose a novel technique that enables the fast tracing of a large number of acoustic beams through the iterative lookup of a special data structure that describes the global visibility between reflectors. The method enables the immediate generation of the beam tree corresponding to an arbitrary source location, which can then be used for path tracing through direct lookup. In practice, this technique generalizes the traditional beam-tracing method as it makes it suitable for real-time acoustic rendering not just when the receiver is moving but also when the source is moving. The method enables real-time modeling of acoustic propagation and real-time auralization in complex 2-D and 2-Dtimes1-D environments (e.g., vertical walls limited by horizontal floor and ceiling), which makes it suitable for applications of real-time virtual acoustics, immersive gaming, and advanced acoustic rendering. Some experimental results show the effectiveness of fast beam tracing with respect to the state of the art in acoustic beam tracing.