We present an interactive algorithm to compute sound propagation paths for transmission, specular refection and edge diffraction in complex scenes. Our formulation uses an adaptive frustum representation that is automatically sub-divided to accurately compute intersections with the scene primitives. We describe a simple and fast algorithm to approximate the visible surface for each frustum and generate new frusta based on specular refection and edge diffraction. Our approach is applicable to all triangulated models and we demonstrate its performance on architectural and outdoor models with tens or hundreds of thousands of triangles and moving objects. In practice, our algorithm can perform geometric sound propagation in complex scenes at 4-20 frames per second on a multi-core PC.

Frustum tracing is a geometric method that allows to perform sound propagation simulation in general complex and dynamic scenes. We describe the underlying algorithm and analyze its behavior with regard to different sampling and scene parameters. We also present an extension of the basic technique that allows to adaptively change the sampling with regard to local geometric complexity and show that this yields the same quality as uniform high sampling at much lower simulation time. We demonstrate our results in an interactive system for intended for virtual environments and prototyping purposes running in real-time on a current high-end PC.

We present a new approach for real-time sound rendering in complex, virtual scenes with dynamic sources and objects. Our approach combines the effenciency of interactive ray tracing with the accuracy of tracing a volumetric representation. We use a four-sided convex frustum and perform clipping and intersection tests using ray packet tracing. A simple and effencient formulation is used to compute secondary frusta and perform hierarchical traversal. We demonstrate the performance of our algorithm in an interactive system for complex environments and architectural models with tens or hundreds of thousands of triangles. Our algorithm can perform real-time simulation and rendering on a high-end PC.

The Impulse Responses (IRs) demonstrating the accuracy of our approach and comparing it with ray tracing techniques. Ray tracing methods could achieve speed performances similar to our algorithm, but not without severe aliasing, as they are not volumetric.