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SCATMECH > Classes and Functions >
Property Models
> Shadow_Function
Abstract class Shadow_Function
The abstract class Shadow_Function is used by Shadowed_Facet_BRDF_Model to store
information about the shadow function. Several
classes inheriting its properties are provided. The user
may provide other shadow functions for Shadowed_Facet_BRDF_Model by creating
classes inheriting the properties of
Shadow_Function.
Instantiable Models and Their Parameters:
| Parameter |
Data
Type |
Description |
Default |
Unit_Shadow_Function:
A trivial shadow function that does not provide any
shadowing. |
| Unit_Shadow_Function has
no parameters.. |
Torrance_Sparrow_Shadow_Function:
A shadow function appropriate for a surface covered
with a distribution of V-grooves, as described by Torrance and Sparrow. |
| Torrance_Sparrow_Shadow_Function
has no parameters.. |
Smith_Shadow_Function:
A shadow function appropriate for Gaussian rough
surfaces, described by Smith. |
| w |
double |
The
standard deviation of the surface slope. |
0.35 |
| Maxwell_Beard_Shadow_Function:
A shadow function developed by
Maxwell and Beard. |
| Omega |
double |
Omega
[deg] |
0.7 |
| tau |
double |
tau
[deg] |
0.25 |
| Table_Shadow_Function:
A shadow function that is interpolated from a table of
values, evaluated at an angle in degrees. The resulting
shadow function is the product of this table evaluated
at each of the incident and scattered polar angles. |
| T |
Table |
The table
containing the shadow function. |
1 |
See also:
SCATMECH Home, Conventions, Shadowed_Facet_BRDF_Model,
K.E. Torrance and E.M. Sparrow, "Theory of
off-specular reflection from roughened surfaces," J. Opt.
Soc. Am. 57(9), 1105-1114 (1967).
B. Smith, "Geometrical Shadowing of a Random Rough
Surface," IEEE Trans. Ant. Prop AP-15, 668-671
(1967).
J.R. Maxwell, J. Beard, S. Weiner,
D. Ladd, and D. Ladd, Bidirectional
Reflectance Model Validation and Utilization,
(Environmental Research Inst. of Michigan (ERIM), Ann
Arbor, MI, 1973).
Include file:
#include "torrspar.h"
Source code:
torrspar.cpp
Definition of public elements:
class Shadow_Function : class Model {
virtual double f(double thetai,double thetas,double phis) = 0;
};
typedef Model_Ptr<Shadow_Function> Shadow_Function_Ptr;
This
function evaluates the shadow function for the given
geometry. The function is defined as that function which
should be multiplied by the calculated intensity to
achieve the shadowed intensity.
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Current SCATMECH version: 7.22 (April 2021)
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