Isotropic Table Roughness


Carbon reflective material associated with isotropic table roughness

Roughness This object allows describing a roughness by a tabulated slope distribution

The table data describes the distribution of surface slope angles

Formally, the table values are the solid angle probability distribution function (pdf) of the local surface normal vector, given at a discrete set of angles to the average surface normal, in degrees. It is not the distribution of angles to the average normal, but a solid angle normal distribution; these are unequal. As the model is restricted to the isotropic case, this solid angle distribution can be reduced to a one dimensional function of the angle.

Between the angles provided in the table, the value is interpolated linearly.

The resulting probability density function does not need to be normalized.

Children nodes








List of angles (first column) and solid angle pdf (second column)

Ocean XML 4.0 example

<roughness type="isotable" name="roughness">
     <param name="distribution" type="list">
             <row angle="0" pdf="1.67556"/>
             <row angle="0.1" pdf="1.55285"/>
             <row angle="0.22" pdf="1.16317"/>
             <row angle="0.36" pdf="0.645422"/>
             <row angle="0.53" pdf="0.248006"/>
             <row angle="0.74" pdf="0.098891"/>
             <row angle="0.99" pdf="0.0788674"/>
             <row angle="1.29" pdf="0.0771793"/>
             <row angle="1.65" pdf="0.0755601"/>
             <row angle="2.08" pdf="0.0731748"/>
             <row angle="2.6" pdf="0.0696985"/>
             <row angle="3.22" pdf="0.0648457"/>
             <row angle="3.96" pdf="0.0583084"/>
             <row angle="4.85" pdf="0.0498455"/>
             <row angle="5.92" pdf="0.039585"/>
             <row angle="7.2" pdf="0.028292"/>
             <row angle="8.74" pdf="0.0173159"/>
             <row angle="10.59" pdf="0.00846904"/>
             <row angle="12.81" pdf="0.00299654"/>
             <row angle="15.47" pdf="0.000665618"/>
             <row angle="18.66" pdf="0"/>