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Open Ocean and Surfzone

Click to see Open Ocean screenshots.

Click to see Surf Zone screenshots.
Open Ocean and Surfzone

Open Ocean Module Features

Interfaces

  • OpenOcean
  • WaveGenerator
  • WaveSpectrum
  • VesselDynamics

OpenOcean

    Rendering Features:
  1. Realistic ocean environment in interactive frame rates (ATI Radeon 9700: 6750 vertices @ 30 frequencies = 30 fps).
  2. Dynamic lighting effects using vertex and pixel shaders.
  3. Environment mapping to reflect sky and clouds on water surface.
  4. Normal map generated from dynamic FFT to simulate high frequency components.
  5. Fresnel lighting to emulate reflection and transmission properties of water.
  6. Ocean color that changes depending on angle with eye vector.
  7. Atmospheric attenuation.
  8. Ocean mesh that rotates and translates with the viewpoint for infinite open ocean.
  9. Vertex culling based on view frustum.
  10. White caps based on wind speed.
  11. LOD management and seaming.
    Programmable Features:
  1. User defined wave coefficients.
  2. User defined environment map.
  3. User defined ocean color.
  4. User defined ocean specularity.
  5. User defined attenuation distance.
  6. User defined NxM ocean patch grid and extent size.
  7. User defined NxM ocean mesh patch grid size.
  8. User defined back face culling.
  9. User defined normal map size.
  10. User defined normal map tile size.
  11. User defined normal map scroll speed.

WaveGenerator

    Modeling Features:
  1. Generates deep ocean sea states 0 to 9 (based on wind speed).
  2. Generates arbitrary number of waves in arbitrary number of directions (multi-freq/multi-directional).
  3. Generates random sea states (all waves created dynamically).
  4. Generates wave coefficients based on a directional spectrum using the Pierson-Moskowitz and Mitsuyasu models.
    Programmable Features:
  1. User defined wind direction.
  2. User defined number of frequencies.
  3. User defined standard deviation of wave directions.

WaveSpectrum

  • Data structure interface for specifying wave coefficients.

VesselDynamics

    Modeling Features:
  1. Deep ocean ship motion (Response Amplitude Operator).
  2. Surf zone ship motion (STWAVE).
  3. Deep ocean bow and stern wake generation.

Surf Zone Module Features
The SurfZone module models crashing waves in near shore areas by:
  1. Stimulating the model with Pierson-Moskowitz deep ocean waves.
  2. Amplifying the wave heights based on the bathymetry.
  3. Determining breakers using an empirical height-wavelength ratio.




Deep Ocean Waves

The deep ocean waves are derived from the Pierson-Moskowitz spectrum, an empirically derived mathmatically model based on real ocean wave data that relates wave energy to wave frequency for a given wind speed. Our deep ocean wave model produces multi-frequency and multi-directional waves for sea states 0 to 9, where the user defines the number of frequencies as well as the dominant wind direction to model.

Wave Amplification

Based on linear shoaling theory, our surf zone model amplifies the wave heights of incoming waves as the bathymetry or depth of the ocean floor decreases. The wave amplification data is derived from the ocean engineering literature [1] which gives the relationship between a depth to wavelength ratio to a wave amplification factor.

Breaker Criteria

The determination of when a wave breaks is derived from empirical ocean engineering literature. The criteria used is based on the wave height to wavelength ratio. If this ratio exceed a certain threshold, the wave is marked as breaking. In the current model, we only consider the plunging class of breakers.

    Modeling Features:

  1. Realistic near shore waves based on Pierson-Moskowitz wave spectrum model.
  2. Wave height amplification based on near shore bathymetry data.
  3. Wave breaking based on dynamic wave parameters.
  4. Multiple wave fronts.
  5. Near shore wave length shortening.
  6. Near shore wave refraction.
    Rendering Features:
  1. Plunging breaker geometry.
  2. Sea spray during breaker initiation.
  3. Sea spray during wave splash-up.
  4. Sea foam during wave run-up.
  5. Spilling breaker geometry.
    Programmable Features:
  1. User defined wave coefficients.
  2. User defined bathymetry data.
  3. User defined surf zone grid and extent size.
References
  1. R. Sorenson. "Basic Wave Mechanics", 1993.






© Dynamic Animation Systems, Inc.