With this daemon it is possible to translate the information of an ocean statistical spectrum or a displacement map into forces. An ocean statistical spectrum, or just OSS, is a method of creating absolutely realistic waves structures. The main purpose is to apply waves of different sizes to a Hybrido fluid surface, but “Ocean Force” also affects standard SPH particles, Hybrido secondaries, and rigid/soft bodies.
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By default, you can see a wavy height field in RealFlow's viewport. This “icon” represents the ocean statistical spectrum based on the daemon's current parameters. This preview helps you to evaluate this wave structure visually. If you prefer other visualization methods you can also switch to a force map or disable this feature completely under “Preview Type”. A way to show the actual forces is to use the daemon's “Display Force Field” function. For more information about how to use this preview option please follow this [ link ] link.
As mentioned above, you will mainly use this daemon to displace a fluid surface and create wave structures – preferably a Hybrido surface. Start with a basic Hybrido scene:
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“Velocity” directly affects the particles from the very beginning without any delay or deceleration. The result is an apparently stronger influence, because the deflection of the particles starts with the very first moment.. “Velocity” is not available for rigid bodies.
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This parameter field is only accessible when “Force type” is set to “Image”. To load an image (sequence), right-click on the small chess board, and choose “Load image”. Then, a new dialogue appears. For a detailed description of the features and parameters of this panel, please take a look at the “Mapped Parameters” chapter below.
Time Factor
If you have already worked with RealFlow's Graphs system or one of the demo scenes, e.g. “apply_stat_spectrum” then you have most probably already seen the “Time factor” setting. This parameter allows you to control the wave surface's speed. Values greater than 1.0 will accelerate the waves, while values smaller than 1.0 can be used to decelerate them. The advantage is that the waves' speed can be adjusted without changing any other parameter. Another plus is that the “Ocean Statistical Spectrum” settings from RealFlow Graphs, Hybrido, and RealWave have been unified as far as possible. This way, you will be able to get exactly the same results with identical settings in all three environments. "Time factor" is a dimensionless value and accepts floats – it works as a multiplier.
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This parameter affects the dispersion of the waves and is only noticed if the length of the wave is close to the value of the depth. In these cases this parameter has a decelerating effect on the wave's dispersion. In most cases you will not see any effects or changes, because depth is normally rather high compared to the length of the waves. The parameter's unit is metres [m].
Dimension
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With this parameter it is possible to change the appearance of the fluid surface. This value can be seen acts like a scaling factor and is given in [m]. When you, for example, enter metres. With a value of 500, the distribution and scale of the waves will look as if the domain covers an a squared area of 500 m x 500 m, although the physical dimensions of the domain did not change at all. Please note that you can enter only one value, because the shape of the displacement is always considered as squared. When you change “Dimension” you will most probably have to modify “@ preview height scale”. “Dimension” and “Resolution” are directly connected:
Level of detail [m] = Dimension [m] :
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Resolution
An example: Let’s assume you have created a surface with a “Quality” “Dimension” of 1024 400 m and a “Resolution” of 400 m1024. The smallest structures you can observe on this ocean will have a size of 0.39 m according to the formula above:
400 m (Dimension) : 1024 (Resolution) = 0.39
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m
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Wind speed
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You can enter any positive or negative value, including 0. “Wind speed” can strongly influence and affect the look of the surface. The parameter's unit is metres per second [m/s].
Wind direction
This is the wind direction
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in
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degrees. If you use
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an axis setup, where Y does not serve as a height axis, the orientation of the wind direction will change.
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With the default
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YXZ orientation
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, RealFlow uses this notation:
- 0°: wind comes from the positive X axis (1,0) - positive wind directions are counter clockwise.
- 90°: wind comes from the positive Z axis (0,1)
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Wind alignment
With small values only waves which are totally perpendicular to the waves' direction are removed. When “Wind alignment” is increased, RealFlow will remove more and more waves; waves which are less perpendicular. If the value is very high, only those waves which are absolutely parallel to the wind direction will remain.
Min Wave Length
With “Min Wave Length” the amount of details on the surface can be controlled. Higher values flatten the surface and create fewer ripples. Please keep in mind that the parameter is connected to “Dimension”. When entering lower values, this parameter should be decreased, too, to guarantee that the RealWave object still shows enough structures.
Weight Against Wind
This is a weighting parameter for waves which are moving to some extent in the opposite direction to the wind. This parameter is used to decrease the number of waves. With
- small values only waves which are totally perpendicular to the waves' direction are removed
- higher settings will remove more and more waves.
Min Wave Length
The amount of surface details can be controlled here:
- Higher values flatten the surface and create fewer ripples
- With smaller “Dimension” values this parameter should be decreased to guarantee that the surface still shows enough structures
Weight Against Wind
If “Weight Against Wind” is 0.0 then all waves against the wind are eliminated. If it is set to 1.0 then its normal strength is used. Values between determine the amount of waves being eliminated.
Seed
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A seed value is used to generate different initial conditions. This helps you to create different looks of the waves with a single click. You might already know this feature from RealWave's “Fractal” modifier. There you can also influence the waves with a new seed. This value is dimensionless and accepts integers.
Repeat U/V
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Since the displacement is calculated from a texture map it is also possible to define the number of repetitions both in U and V direction of the mesh grid. U and V coordinates are related to the UV grid that is created with the mesh. Displacement maps are seamless, though very high values are very likely to create regular patterns on the surface. This value is dimensionless and accepts integers.
Preview Type
Here you can define how the force field should be displayed in the viewport. “None” disables the representation of the height field, but the domain's bounding box and icon are still visible. Their visibility is controlled under “Display”. “Surface” is the default option and shows the ocean statistical spectrum in a 3D viewport representation. “Magnitude texture”, on the other hand, visualizes the daemon's force field in the form of a coloured map: red indicates high forces, while blue colours stand for low forces.
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