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Description
Defines a Mie volume scatter model for a material and is therefore the volumetric (3D) equivalent of the (2D) Mie Surface Scatter.
In the same manner as for the surface scatter model, the volume scatter calculation relies on a numeric integration of the scatter distribution over the range of particle sizes, and to achieve this the particulate distribution range is divided into N bins that, when using Uniform or Gaussian distributions, are evenly spaced between the min and max particle sizes for that distribution. During the raytrace a particle size is randomly chosen according to the particle distribution function and the precomputed particle size closest to that random size is used to determine the scattered ray direction. The values of N for each distribution is listed in the table below. Note that for Sampled distributions the number of bins is simply taken from the number of data points (rows) provided in the table.
This feature is not compatible for use with coherent raytracing.
Navigation
This feature can be accessed in the following ways:
•From a materials dialog select the "Volume Scatter" tab, then select "Mie" as the type.
Controls
When the Type is set to Mie the following controls are available:
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Control
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Inputs / Description
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Defaults
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Wavelength
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Reference wavelength for the calculation
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0.5
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N immerse
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Sets the particle immersion real refractive index (typically this should be set to the material index at the reference wavelength)
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1
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N particle
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Sets the particle real refractive index
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1.5
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K particle
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Sets the particle imaginary refractive index
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0
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Diameter Function
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Sets the particle distribution type which defines a statistical distribution of particle diameters, options are "Uniform", "Gaussian" or "Sampled"
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Uniform
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The remainder of the table follows the diameter function selection as follows:
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Diameter Function = Uniform [N=11]
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Dia min
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Minimum particle diameter (um)
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1
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Dia max
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Maximum particle diameter (um)
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1
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Diameter Function = Gaussian [N=29]
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Dia min
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Minimum particle diameter (um)
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0.5
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Dia max
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Maximum particle diameter (um)
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2
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Dia peak
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Particle diameter (um) at Gaussian peak
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1.25
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Dia variance
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Semi-width (variance in um) of the Gaussian particle diameter distribution
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1
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Diameter Function = Sampled [N=no. of data points]
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Particle Dia (um)
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Particle diameter for given row in table
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1
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Relative Particle Diameter Density
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Relative Particle Diameter Density for given row in table
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1
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Related Topics
Volume Scatter
Scripted Volume Scatter model
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