1. Sound Simulation Project The Sound of Thunder Simulation Sang Woo Lee(leejswo@cs.unc.edu)leejswo@cs.unc.edu

2. 2015-12-012 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)

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 2015-12-013

4. 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

5. 2015-12-015 Previous Works Katsutsugu Matsuyama, Tadahiro Fujimoto, Norishige Chiba,“Real-time Sound Generation of Spark Discharge” Expand to general electric spark discharge

6. 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) 2015-12-016

7. 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

8. 2015-12-018 References 1.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