Refractive BSDF

Description

../../../_images/refractive.jpg

Example of refractive sandblasted soda-lime glass

BSDF This model corresponds to rough reflective and refractive materials. It works similarly to the specular type, except the surface is rough, and causes scattering.

Rough transparent surfaces are often used with a bulk medium (see modelling volumes) : this means they do not describe only surface properties, but also what happens to light within their volume. The medium associated to the material governs refraction, and volumetric light extinction.

Reflection and transmission coefficients are governed by the defined intlaw. This can range from simple fresnel law (assuming the material is a simple diopter between internal and surrounding medium) to complex optical surfaces.

This BSDF model is one of the most complex handled by Ocean. Simulations can take a significant time to resolve, as they generate a very large number of significantly contributing paths, taking into account roughness, polarization, refraction and dispersion, combined with advanced interface laws such as coatings.

For modelling a non-transparent rough surface, please refer to the Reflective BSDF.

Note

In Ocean 2015 and earlier versions, this corresponds to the rough transparent material

Children Nodes

Interface law intlaw

Optical law governing reflection and transmission coefficients

Roughness roughness

Surface microscopic roughness distribution

Parameters

name

type

description

rereflections

boolean

If set to true (by default), Ocean simulates first order rereflections on the roughness. This is more accurate, but slower. The effect is more visible with very rough surfaces

Ocean XML 6.1 example

<material type="generic" name="previewmaterial">
     <medium type="simple" name="bulk" precedence="10">
             <dielectricfunc type="na" name="dielectricfunc">
                     <spectrum type="cauchy" name="n" b="1.5235" c="0.00424672"/>
                     <spectrum type="tabulated" name="a">
                              3.8e-07        13.93   3.9e-07 8.53    4e-07   5.21    4.1e-07 5.44    4.2e-07 6.05    4.3e-07 5.72    4.4e-07 5.76    4.5e-07 5.43    4.6e-07 5.1     4.7e-07 4.02
                              4.8e-07        2.77    4.9e-07 3.32    5e-07   3.92    5.1e-07 3.78    5.2e-07 3.97    5.3e-07 3.27    5.4e-07 2.9     5.5e-07 3.31    5.6e-07 3.87    5.7e-07 3.91
                              5.8e-07        4.84    5.9e-07 5.63    6e-07   6.01    6.1e-07 6.8     6.2e-07 7.75    6.3e-07 8.51    6.4e-07 9.13    6.5e-07 10.28   6.6e-07 10.85   6.7e-07 11.67
                              6.8e-07        12.65   6.9e-07 14.02   7e-07   14.81   7.1e-07 16.04   7.2e-07 17.04   7.3e-07 18.25   7.4e-07 19.06   7.5e-07 19.92   7.6e-07 21.14   7.7e-07 21.97
                              7.8e-07        23.21
                     </spectrum>
             </dielectricfunc>
     </medium>
     <bsdf type="refractive" name="bsdf" rereflections="true">
             <roughness type="phong" name="roughness">
                     <scalarshader type="uniform" name="exponent" value="10"/>
             </roughness>
             <intlaw type="fresnel" name="intlaw"/>
     </bsdf>
</material>