Ming C. Lin

Recently, many physically accurate algorithms have been proposed for interactive sound propagation based on geometric and wave-based methods. In terms of these applications, a key question arises whether the improved physical accuracy of these algorithms offers perceptual benefits over prior interactive methods? In this work, we present results from two studies that compare listeners' perceptual response to both accurate and approximate propagation algorithms that are used to simulate two key acoustic effects: diffraction and reverberation. For each effect, we evaluate whether increased numerical accuracy of a propagation algorithm translates into increased perceptual differentiation in interactive environments. Our results suggest that auditory perception indeed benefits from the increased accuracy, with subjects showing better perceptual differentiation when experiencing the more accurate propagation method. The diffraction experiment exhibits a more linearly decaying sound field (with respect to the diffraction angle) for the accurate diffraction method, while the reverberation experiment shows that more accurate reverberation results in better assessment of room volume and acoustic distance perception. In case of room volume, accurate reverberation, after modest user experience, results in a near-logarithmic response to increasing room volume. Finally, in the case of acoustic distance perception, accurate reverberation shows less distance compression as compared to an approximate, filter-based reverberation method.

3D digital models of complex systems is often used to reduce design time, lower testing and validation cost, perform virtual rehearsal'', and rapid visualization of intricate datasets of varying scale: from nanometer-sized objects (e.g. nanoscale robots, storage devices and nanowheels), biological entities (e.g. human bodies), physical systems (e.g. chemical propagation), environmental data (e.g. terrain and urban environments), to large-scale man-made computer-aided design (CAD) structures (e.g. unmanned aerial vehicles, tanks and combat vehicles, underwater robots, and powerplants composed of many millions of parts). In this proposal, we refer to the 3D digital representations of of these extremely large and massive systems as giga-models''. To help fully realize the potential of virtual environments, the proposed research targets the solution of several important and well-defined problems, including interactive display, proximity queries, and physical simulation.

We propose to address some fundamental research issues in handling and visualizing massive models, composed of millions of primitives. These include efficient representations, interactive display and real-time interaction. These models arise in many applications, including computer-aided design, simulation-based design, lethality and vulnerability analysis, medical simulation, surgical training and scientific visualization. Our goal is to develop efficient algorithms and systems, and demonstrate their performance on massive environments composed of millions of primitives.

This special issue addresses some of the challenges in this field through papers presented by researchers covering: hardware trends; programming and software challenges; and applications. The nine papers are summarized here.