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Crash, Bang, Rumble! Bringing Noise to Virtual Worlds

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falling shells

Whether metal or plastic, objects made up of thin shells have a characteristic way of making noise that can be simulated by a computer to synthesize sound for animated films and virtual reality.

Credit: James Lab / Cornell University

Cornell University computer scientists have developed a method for generating the crashing and rumbling noises of objects made from thin harmonic shells such as cymbals and garbage can lids. The method, developed by professor Doug James and graduate students Jeffrey Chadwick and Steven An, will be presented at ACM's SIGGRAPH Asia conference, which takes Dec. 16-19 in Yokohama, Japan.

When a thin-shelled object falls or is struck, the metal or plastic slightly deforms and then snaps back into place, creating a vibration. Previous methods of synthesizing these noises did not account for the coupling effect that occurred when energy transfers from one vibration to another and back again, which resulted in a clean, clear sound that is more appropriate for a bell or chime. The new method accounts for this interaction and maps how the sound waves radiate to determine how the event will sound to a listener in any particular location.

The researchers say that although their method is significantly faster than existing systems, the computations for a simple demonstration still take about an hour on a laptop. However, the researchers are hopeful that the simulation process can be accelerated by making some approximations. Their research is part of a larger project to synthesize various sounds, including dripping and splashing fluids, small clattering objects, and shattering glass.

From Cornell Chronicle
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Abstracts Copyright © 2009 Information Inc., Bethesda, Maryland, USA


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