Notes

Outline

CS 563 Advanced Topics in Computer Graphics  Statistical Wave Models  by Daniel Mooney

Introduction Recover realistic geometric wave models from statistical data Use technique outlined in [1Jen] and [2Tes] Render height field via 3DSMax

Review of method Statistical wave models are the current trend Not based on physical models, instead uses statistical models based on observations of the real ocean Uses measured wave spectra Notable: Pierson-Moskowitz, JONSWAP ( Joint North Sea Wave Project ) and Phillips spectra High levels of realism are limited to relatively calm conditions Commercially pioneered in Waterworld and Titanic Preferred method in today’s CG Described in detail in Tessendorf  [2Tes] and Jensen, et al  [1Jen] Prior use confined to the optical oceanography community Synthesizes a height field from a FFT prescription The model is two-fold Use statistical data to generate the height field data in the frequency domain Retrieve the spatial height field from the frequency data via the inverse DFT( FFT )

Height field examples Height field A: t=0, depth=100m Wind vector=(0.0,1.0), wind speed=31m/s Size=(400m,400m), Res=(256,256)

Height field examples Height field B: t=0, depth=100m Wind vector=(1.0,0.0) Wind speed=31m/s Size=(200m,200m), Res=(128,128)

Rendered example

Modeling Waves and Water References [1Jen] L.S.Jensen and R.Goliáš, Deep-Water Animation and Rendering [2Tes] J.Tessendorf, Simulating Ocean Water, SIGGRAPH Course Notes, 2001