Sound Simulation Project

The Sound of Thunder Simulation

Sang Woo Lee(leejswo@cs.unc.edu)

23年 4月 21日 2

Motivation

• Can we generate sound of thunder correctly?

• Is the sound of thunder in movie SFX is correct? (ex. Lightning bolt of Fantasy movie, spark ball discharging in Terminator 3)

Lightning & Thunder

• Lightning– An electric spark discharge– Breakdown of air– Air molecules dissociated into electrons and

ions, and electric current flow– Light and sound are emitted

• Thunder– The sound caused by lightning– Caused by extreme heating of air– Only 1% remains travel– Consists of shock wave

23年 4月 21日 3

23年 4月 21日 4

Previous Works

• Glassner, A., “The Digital Ceraunoscope: SyntheticThunder and Lightning”

• Seems to be the first paper about synthetic thunder• Create thunder sound using the shape and patterns of

the lightning

23年 4月 21日 5

Previous Works

• Katsutsugu Matsuyama, Tadahiro Fujimoto, Norishige Chiba,“Real-time Sound Generation of Spark Discharge”

• Expand to general electric spark discharge

Previous Work• Generating lightning path

– Tree shaped

• Synthesizing sound of thunder– Approximated by N-wave– Waveform is elongated as the sound

propagates– Decaying faster than linear– Using WM-wave (integrating N-wave over a

line)

23年 4月 21日 6

23年 4月 21日 7

Goals

• Simulate the sound of thunder using previous model

• Added new features– Sound of cloud-to-cloud discharge

• Thunder storm is coming!

– Sound dispersion by cloud– Reflection/refractions of landscape

23年 4月 21日 8

References1. Glassner, A., “The Digital Ceraunoscope: Synthetic

Thunder and Lightning, part1”, IEEE computer graphics and applications, 20(2), pp. 89-93, 2000.

2. Glassner, A., “The Digital Ceraunoscope: Synthetic Thunder and Lightning, part2”, IEEE computer graphics and applications, 20(3), pp. 92-96, 2000.

3. Matsuyama, K. et al., “Real-time Sound Generation of Spark Discharge”, pg, pp. 423-426,  15th Pacific Conference on Computer Graphics and Applications (PG'07),  2007