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Iridescent#

The Iridescent material is both reflective and iridescent. The material is composed of a diffuse and reflection component. It approximates the property of surfaces that have their reflected color varying in function of the angle of view and the angle of light.

It simulates a surface made by thin film layers separated by air spaces, resulting in a rainbow effect like on soap bubble, sunglasses or butterflies wings. This material supports reflection caustics.

Iridescent Material

Diffuse#

The diffuse component of the material is controlled by a set of attributes which defines the diffuse diffusion of the material.

Attribute Description
Diffuse Brdf Define the BDRF model used for the diffuse component. The material supports 2 models: Lambert (extended) and Oren Nayar
Diffuse Color Define the diffuse color of the material.
Diffuse Gain Define the gain of the diffuse reflection.
Diffuse Roughness Define the surface roughness of the diffuse component.

Diffuse Gain 0%

Diffuse Gain 25%

Diffuse Gain 50%

Diffuse Gain 75%

Diffuse Gain 100%

Reflection#

The reflection component of the material is controlled by a set of attributes which defines the reflectivity of the material.

Attribute Description
Reflection Color Define the color of the reflection.
Reflection Gain Define the gain of the reflection.
Reflection Exit Color Define the color returned by the path tracer when the path has reached the maximum reflection depth set in the path tracer.
Fresnel Ior Define the index of refraction of the surface.
Reflection Roughness Define the surface roughness of the reflection component.

Reflection Gain 0%

Reflection Gain 25%

Reflection Gain 50%

Reflection Gain 75%

Reflection Gain 100%

Fresnel#

Fresnel IOR 10

Fresnel IOR 125

Fresnel IOR 15

Fresnel IOR 175

Fresnel IOR 20

Roughness#

The material supports Roughness and multiple microfacet models that can be selected using the Brdf attribute.

BRDF Description
GGX GGX distribution results are very close to empirical data.
Ward Ward distribution is very close to Beckmann's but behave quite differently with anisotropy
Beckmann Beckmann distribution tends to provide sharper reflections when compared to GGX

Reflection Roughness 0%

Reflection Roughness 25%

Reflection Roughness 50%

Reflection Roughness 75%

Reflection Roughness 100%

Iridescence#

The iridescence effect is controlled by a set of attributes which defines the physical property of the material.

Attribute Description
Iridescent Exposure Define the exposure of the iridescence.
Iridescent Power Define the exponent for the iridescence which corresponds to the interference power that is proportional to the number of thin layers constituting the material.
Iridescent Film Thickness Define the thickness of the film layers (in nanometers) through which the light is refracted.
Iridescent Air Thickness Define the thickness of the air layers (in nanometers) which corresponds to the spacing between the thin film layers.
Iridescent Diffuse Enable the iridescent absorption on the diffuse component of the material.
Iridescent Reflection Enable the iridescent absorption on the reflection component of the material.

Exposure#

Iridescent Exposure 00

Iridescent Exposure 15

Iridescent Exposure 30

Iridescent Exposure 45

Iridescent Exposure 60

Power#

Iridescent Power 00

Iridescent Power 05

Iridescent Power 10

Iridescent Power 15

Iridescent Power 30

Film Thickness#

Iridescent Film Thickness 1000

Iridescent Film Thickness 1250

Iridescent Film Thickness 1500

Iridescent Film Thickness 1750

Iridescent Film Thickness 2000

Air Thickness#

Iridescent Air Thickness 00

Iridescent Air Thickness 500

Iridescent Air Thickness 1000

Iridescent Air Thickness 1500

Iridescent Air Thickness 2000