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.
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. |
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. |
Fresnel#
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 |
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#
Power#
Film Thickness#
Air Thickness#
