Fresnel Equation Node

Description

The Fresnel Equation Node adds equations that affect Material interactions to the Fresnel Component. You can select an equation in the Mode dropdown.

You can find Numerical values of refractive indices at refractiveindex.info.

Ports (Schlick)

Name	Direction	Type	Binding	Description
f0	Input	Vector{1, 2, 3}	None	Represente the reflection of the surface when we face typically 0.02-0.08 for a dielectric material.
DotVector	Input	Float	None	The dot product between the normal and the surface.
Fresnel	Output	same as f0	None	Fresnel coefficient, which describe the amount of light reflected or transmitted.

Ports (Dielectric)

Name	Direction	Type	Binding	Description
IOR Source	Input	Vector	None	The refractive index of the medium the light source originates in.
IOR Medium	Input	Vector	None	The refractive index of the medium that the light refracts into.
DotVector	Input	Float	None	The dot product between the normal and the surface.
Fresnel	Output	same as f0	None	The fresnel coefficient, which describe the amount of light reflected or transmitted.

Ports (DielectricGeneric)

Name	Direction	Type	Binding	Description
IOR Source	Input	Vector	None	The refractive index of the medium the light source originates in.
IOR Medium	Input	Vector	None	The refractive index of the medium that the light refracts into.
IOR MediumK	Input	Vector	None	The refractive index Medium (imaginary part), or the medium causing the refraction.
DotVector	Input	Float	None	The dot product between the normal and the surface.
Fresnel	Output	same as f0	None	Fresnel coefficient, which describe the amount of light reflected or transmitted.

Controls

Name	Type	Options	Description
Mode	Dropdown	• Schlick: This mode produces an approximation based on Schlick's Approximation. Use the Schlick mode for interactions between air and dielectric materials. • Dielectric: Use this mode for interactions between two dielectric Materials. For example, air to glass, glass to water, or water to air. • DielectricGeneric: This mode computes a Fresnel equation for interactions between a dielectric and a metal. For example, clear-coat- to metal, glass to metal, or water to metal. Note: if the IORMediumK value is 0, DielectricGeneric behaves in the same way as the Dielectric mode.

Generated Code Example

The following example code represents one possible outcome of this node.

void Unity_FresnelEquation_Schlick(out float Fresnel, float cos0, float f0)
{
    Fresnel = F_Schlick(f0, cos0);
}

void Unity_FresnelEquation_Dielectric(out float3 Fresnel, float cos0, float3 iorSource, float3 iorMedium)
{
    FresnelValue = F_FresnelDielectric(iorMedium/iorSource, cos0);
}

void Unity_FresnelEquation_DielectricGeneric(out float3 Fresnel, float cos0, float3 iorSource, float3 iorMedium, float3 iorMediumK)
{
    FresnelValue = F_FresnelConductor(iorMedium/iorSource, iorMediumK/iorSource, cos0);
}

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