COMP790-058 Sound Simulation Project Homepage
 The Sound of Thunder Simulation
Sang Woo Lee

Project Title: The Sound of Thunder Simulation

800px-Thunder_rym.png

 

Proposal PPT

 

Final Project Report

 

Motivation:

This project is started from very simple questions: Can we simulate sound of thunder correctly? Is the sound effect of movie SFX is physically correct? For example, when we see lightning bolt hit the enemy, the sound effect is based on physical modeling? Is the sound of spark discharging ball in Terminator series are realistic? Therefore, I tried to find realistic sound of thunder.

ball lightning.jpg

 

 

Background for lightning and thunder:

Spark discharges occur when extremely high voltages are applied to insulators and break them down. In insulator breakdown, the olecules of the insulator are dissociated into electrons and ions. These particles carry electric charge, and their motion is itself the definition of an electrical current flow. Light and sound are emitted when the molecules are dissociated.

Lightning is a spark discharge occurring in the breakdown of air, which acts as the insulator. A thunderbolt consists of one or more discharges called lightning strikes. Each lightning strike is a combination of a leader and a return stroke. A leader is the initial discharge that occurs when the air undergoes breakdown, and the return stroke is a discharge in the opposite direction that follows the same path of the leader.

Thunder is sound consists of shock wave caused by lightning, which results extreme heating of the air. The 99% of shock wave energy is dissipated within few meters, so only 1% of shock wave energy remains travels as an acoustic wave.

 

Synthesizing sound of thunder from previous work:

We can approximate the sound of thunder using N-wave. This waveform is elongated as the sound propagates, and decayed faster than linear. As the lightning is consists on line segments, we can approximate the total waveform using WM-wave, which is integration of N-wave over a line.

waveforms.png

 

 

Goals:

1.      Simulate the sound of thunder using previous model

2.      Simulate sound of cloud-to-cloud discharge

3.      Simulate sound dispersion by cloud

4.      Simulate reflection/refraction of landscape

 

Reference:

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