# Iridescent#

(MaterialPhysicalIridescent)

• Category: /Material/Physical
• Default object name: iridescent

Go to Technical page.

## Description#

Iridescent material

## Attributes#

Name Type Description
Export Aovs bool Compute and write Aovs defined in the shading graph
Arbitrary Output Variables reference (AovStore) Set the list of extra channels to write to the image.
Light Path Expression Label string Set the material label in light path expressions.
Material Sample Count long Material sample count per pixel.
Diffuse Sampling Multiplier double Material diffuse sample count multiplier.
Glossy Reflection Sampling Multiplier double Material glossy reflection sample count multiplier.
Russian Roulette double Amount of Russian roulette used on the material samples.
Roughness Noise Optimization double Noise reduction strategy along rough light path.
Multiple Scattering Strength double Strength of compensation for energy lost by multiple scattering.
Diffuse Depth long Maximum diffuse depth.
Specular Reflection Depth long Maximum specular reflection depth.
Glossy Reflection Depth long Maximum glossy reflection depth.
Opacity double[3] Opacity of the material.
Normal Mode long Define which geometric normal to use for the shading.
Normal Input double Override the shading normal by the one given as input. The value controls the blending with the original normal.
Sidedness long Sidedness of this surface used for this material. 'Single' keeps the original normals no matter what. 'Double' may flip the normal to be oriented toward the incomming direction. 'Invert' flips the original normal no matter what.
Shadow Casting Mode long Defines the properties of the material when casting shadows: fully opaque (regardless of the actual value of the opacity of the material), artistic (user-defined opacity and coloring), pseudo-caustics (cheaply emulating actual refractive caustics) or physical (intrinsic transparency of the material), where the last three are modulated by the opacity of the material.
Shadow Opacity double Defines how dark the shadows cast by this material are.
Shadow Coloring double Defines how much refraction and absorption colors affect shadowing.
Reflective Caustics long Reflective caustics computation mode.
Diffuse Brdf long BRDF used for the diffuse reflection. The Lambertian model is augmented with a Fresnel term to approximate rough diffuse reflection. The Oren-Nayar BRDF better models back-scattering effects that characterize rough diffuse reflection, accounting for both single and double bounces of light onto the micro-geometry of the surface.
Diffuse Color double[3] Define the diffuse color.
Diffuse Gain double Diffuse gain of the diffuse color.
Diffuse Roughness double Roughness of the diffuse surface. For Fresnel Lambertian, values smaller than 50% slightly darken grazing angles, and values greater than 50% give the silhouettes a subtle glow (albeit potentially violating energy conservation), whereas a midrange value approaches (but differs from) the pure Lambertian model. For Oren-Nayar, a zero value yields the pure Lambertian model, whereas greater values increase backward scattering phenomena.
Brdf long BRDF used for the reflection.
Reflection Color double[3] Define the reflection color.
Reflection Gain double Reflection gain of the reflection color.
Reflection Exit Color double[3] Set the reflection color when there is no more bounce along the path.
Fresnel Ior double Set the index of refraction.
Reflection Roughness double Roughness of the reflection surface.
Iridescent Exposure double Iridiscent exposure.
Iridescent Power double Exponent for the iridescence, corresponds to the interference power which is proportional to the number of thin layers constituting the material.
Iridescent Film Thickness double Thickness of the film layers (expressed in nanometers), through which light is refracting.
Iridescent Air Thickness double Thickness of the air layers (expressed in nanometers), in other words spacing between the film layers.
Iridescent Diffuse bool Enables/disables iridescent absorption on the diffuse component.
Iridescent Reflection bool Enables/disables iridescent absorption on the specular component.