Rough transparent material

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Example of rough transparent sandblasted soda-lime glass
material-2014.png

Description

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

Rough transparent materials are often used with a bulk medium : 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 interface law. This can range from simple fresnel law (assuming the material is a simple diopter between internal and surrounding medium) to complex optical surfaces.

This material 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 reflective material type.

Children nodes

intlaw-2014.png intlaw
Interface law : Optical law governing reflection and transmission coefficients
roughness-2014.png roughness
Roughness : Surface small-scale roughness distribution. It is currently restricted to non-specular (non-zero) roughnesses
medium-2014.png bulk
Medium : The bulk medium filling the geometry volume on the back side
normalshader-2014.png bump
Normal shader : Normal shading modifier
emitter-2014.png emitter
Emitter : The Surface light emission properties


Parameters

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
polarized
boolean
If set to true (by default), Ocean computes accurate polarization state for reflections/refractions. When set to false, a faster, more simple yet less accurate unpolarized model is used for this material

Ocean XML 2.0 example

<?xml version="1.0" encoding="UTF-8"?>
<oceanroot version="2.0">
<material name="frostglass" type="roughtransparent">
	<medium name="bulk" precedence="10" type="simple">
		<spectrum name="n" type="cauchy" b="1.5235" c="0.00424672"/>
		<spectrum name="a" type="tabulated" start="380E-9" end="780E-9" num="41">
			13.93	8.53	5.21	5.44	6.05	5.72	5.76	5.43	5.10
			4.02	2.77	3.32	3.92	3.78	3.97	3.27	2.90	3.31
			3.87	3.91	4.84	5.63	6.01	6.80	7.75	8.51	9.13
			10.28	10.85	11.67	12.65	14.02	14.81	16.04	17.04	18.25
			19.06	19.92	21.14	21.97	23.21			
		</spectrum>										
	</medium>
	<prm rereflections="true" polarized="true"/>
	<intlaw name="intlaw" type="fresnel"/>
	<roughness name="roughness" type="phong">
		<scalarshader name="exponent" type="uniform" value="10"/>
	</roughness>
</material>
</oceanroot>

See also

Material types