Fresnel 菲涅耳

Introduction

引言

This shader node computes a Fresnel effect weighted color. The Fresnel effect determines how the reflectivity of a surface changes when an incident ray is parallel vs perpendicular to the surface normal, with the reflectivity being strongest when perpendicular. This node is useful for effects such as controlling color ramps that change with viewing angle or blending material reflection layers in a physically correct way.

这个着色器节点计算菲涅耳效应加权颜色。菲涅耳效应决定了入射光线平行于垂直于表面法线时表面反射率的变化，垂直于表面法线时反射率最强。这个节点是有用的效果，如控制颜色斜坡，改变视角或混合材质反射层在物理上正确的方式。

Above shows an example of the 'Fresnel effect' of facing reflectivity vs perpendicular reflectivity, tinted green to highlight the effect

上图展示了一个菲涅耳效应的例子，面对反射率和垂直反射率，着绿色突出效果

Parameters

参数

Falloff Color

Use Index of Refraction

使用折射率

This allows you to toggle between a cheap Schlick Fresnel computation that does not require an Index of Refraction and a more complex, but more correct, method that does.

这样你就可以在不需要折射率的廉价 Schlick Fresnel 计算和更复杂但更正确的方法之间进行切换。

Curve Falloff

曲线下降

When Use Index of Refraction is disabled, this option controls the shape of the Fresnel fall-off curve as it transitions between the Facing Color and the Perpendicular Color.

当使用折射率被禁用时，这个选项控制菲涅尔下降曲线的形状，因为它在正面颜色和垂直颜色之间过渡。

Facing Color

面向色彩

This is the color when the incident ray is parallel to the surface normal.

这是当入射光线平行于表面法线时的颜色。

Perpendicular Color

垂直色

This is the color when the incident ray is perpendicular to the surface normal.

这是入射光线垂直于表面法线时的颜色。

IOR

返回抑制

The scientific IOR and k values for metal materials can seem non-intuitive, but a wide range of them can be found at this website: http://refractiveindex.info/

金属材料的科学 IOR 和 k 值看起来不那么直观，但是在这个网站上可以找到大量的 IOR 和 k 值: http://refractiveindex.info/

Index of Refraction

折射率

When Use Index of Refraction is enabled, this is the value that describes the index of refraction. For non-metals, the facing Fresnel reflectivity is pretty dim and this value should be between 1.0 and 2.0.

如果启用了使用折射率，这个值就是描述折射率的值。对于非金属材料，面向菲涅耳反射率较低，应在1.0 ~ 2.0之间。

Extinction Coefficient (k)

消光系数(k)

This controls the 'k' part of complex IOR, which is required for metals. It should be left at 0.0 for non-metals.

这控制复杂 IOR 的“ k”部分，这是金属所必需的。对于非金属，应该保持在0.0。

Correct Facing Color Intensity

正确面对颜色强度

When this option is enabled, the Facing Color intensity is corrected to better match the computed Fresnel reflectivity, for more realistic results.

当这个选项被启用，面临的颜色强度被修正，以更好地匹配计算菲涅耳反射率，为更真实的结果。