Hair 头发
Introduction
引言
The hair shader simulates the complex, anisotropic reflections that are typically found in real hair and fur. Redshift takes inspiration from the paper 'An Artist Friendly Hair Shading System' by Sadeghi et al, which simplifies the Marschner shading model and introduces controls that are more intuitive, while maintaining realistic rendering results. Redshift further simplifies the Sadeghi shading model into three reflections:
头发着色器模拟复杂的，各向异性的反射，通常发现在真正的头发和毛皮。红移的灵感来自 Sadeghi 等人的文件友好的艺术家头发着色系统，它简化了 Marschner 着色模型，并引入了更直观的控件，同时保持了真实的渲染结果。进一步简化 Sadeghi 着色模型为三个反射:
- Internal reflection, which is light that has entered the hair and reflected back out. This reflection is responsible for the overall color of the hair. 内部反射，即光线进入头发并反射出来。这种反射决定了头发的整体颜色
- Transmission, which is light that has entered the hair and reflected through the back-side. This reflection is responsible for the back-lit translucency effect. 透射，即光线进入头发并通过头发后面反射。这种反射是负责的背光半透明效果
- Primary reflection, which is light that is reflected off the surface of the hair. This reflection is responsible for the shininess. 初级反射，即头发表面反射的光线。这种反射是光亮的原因
Our shader also supports a basic diffuse component, which allows you to cheaply illuminate the hair, without requiring extra reflection bounces. Use the diffuse with caution though, as it may make the hair look flat and unrealistic.
我们的着色器还支持一个基本的漫反射组件，它可以让你廉价地照亮头发，而不需要额外的反射反弹。小心使用头发分散剂，因为它可能会使头发看起来扁平和不现实。
General
将军
Internal Reflection
内部反射
Color
颜色
This is the color of the internal reflection. This defines the color of the hair.
这是内部反射的颜色。这定义了头发的颜色。
Weight
重量
This scales the overall amount of the internal reflection.
这可以缩放内部反射的总量。
Glossiness
光泽度
This controls the longitudinal glossiness of the reflection along the hair strand. A glossiness of 1 means almost mirror reflection, while a glossiness of 0 means a deviation of around 30 degrees, for a very rough reflection. Internal Reflections are typically rough compared to primary reflection, which yields a more diffuse look.
这控制了沿着发丝反射的纵向光泽度。光泽度为1意味着几乎是镜面反射，而光泽度为0意味着30度左右的偏差，因为反射非常粗糙。内部反射通常是粗糙的相比，主要的反射，这产生一个更漫反射的外观。
Samples
样本
This defines the number of samples to use for the reflection. More samples means less noise.
这定义了用于反射的样本数量。更多的样本意味着更少的噪声。
Highlights Only
仅限重点
This optimization option defines whether only lights are sampled for the reflection. Disabling this means 'indirect' lighting from surrounding objects and environment maps will also be sampled.
It is recommended that this option is disabled for GI, in order to catch indirect lighting contributions.
此优化选项定义是否只为反射采样灯。禁用这意味着“间接”照明从周围的物体和环境地图也将采样。建议对 GI 禁用此选项，以捕捉间接照明的贡献。
Diffuse
漫反射
Color
颜色
This is the color of Lambertian diffuse component. This contributes extra color to the hair.
这是兰伯特漫反射成分的颜色，这使得头发有了额外的颜色。
Weight
重量
This scales the overall amount of the diffuse.
这可以缩放漫反射的总量。
Translucency Weight
半透明重量
This scales the overall amount of diffuse translucency, which is the diffuse back-lit lighting.
这是漫反射半透明的整体数额的规模，这是漫反射背光照明。
This diffuse lighting effectively replaces the anisotropic Transmission, so the stronger this weight, the weaker the anisotropic Transmission contribution will be. When this weight is 1.0, there is no Transmission lighting.
这种漫射照明有效地替代了各向异性透射，因此该权重越大，各向异性透射贡献就越小。当这个重量是1.0，没有传输照明。
Transmission
传输
Color
颜色
This defines the color of the transmission.
这定义了传输的颜色。
Weight
重量
This scales the overall amount of the transmission.
这个比例是传播的总量。
Length Glossiness
长度光泽度
This controls the longitudinal glossiness of the reflection along the hair strand. A glossiness of 1 means almost mirror reflection, while a glossiness of 0 means a deviation of around 30 degrees, for a very rough reflection.
这控制了沿着发丝反射的纵向光泽度。光泽度为1意味着几乎是镜面反射，而光泽度为0意味着30度左右的偏差，因为反射非常粗糙。
Width Glossiness
宽度光泽度
This controls the azimuthal glossiness of the reflection along the hair strand. A glossiness of 1 means almost mirror reflection, while a glossiness of 0 means a deviation of around 30 degrees, for a very rough reflection.
这控制了沿着头发丝反射的方位光泽度。光泽度为1意味着几乎是镜面反射，而光泽度为0意味着30度左右的偏差，因为反射非常粗糙。
Primary Reflection
初级反射
Color
颜色
This defines the color of the primary reflection.
这定义了主反射的颜色。
Weight
重量
This scales the overall amount of the primary reflection.
这可以缩放主反射的总量。
Glossiness
光泽度
This controls the longitudinal glossiness of the reflection along the hair strand. A glossiness of 1 means almost mirror reflection, while a glossiness of 0 means a deviation of around 30 degrees, for a very rough reflection.
这控制了沿着发丝反射的纵向光泽度。光泽度为1意味着几乎是镜面反射，而光泽度为0意味着30度左右的偏差，因为反射非常粗糙。
Samples
样本
This defines the number of samples to use for the reflection. More samples means less noise.
这定义了用于反射的样本数量。更多的样本意味着更少的噪声。
Highlights Only
仅限重点
This optimization option defines whether only lights are sampled for the reflection. Disabling this means 'indirect' lighting from surrounding objects and environment maps will also be sampled.
It is recommended that this option is disabled for GI, in order to catch indirect lighting contributions.
此优化选项定义是否只为反射采样灯。禁用这意味着“间接”照明从周围的物体和环境地图也将采样。建议对 GI 禁用此选项，以捕捉间接照明的贡献。
Angular Shift
角移
Hair is made up of tiny scales. This option allows you to specify the tilt of those scales. Values are typically in the range -10 to -5 degrees.
头发是由微小的鳞片组成的。此选项允许您指定这些天平的倾斜。值通常在 -10到 -5度范围内。
Enable Fresnel
启用菲涅耳
Enables Fresnel reflection fall-off, so reflections perpendicular to the camera will be brighter than when facing the camera.
使菲涅耳反射下降，因此垂直于相机的反射将比面对相机时更明亮。
IOR
返回抑制
The index of refraction which is used to compute the Fresnel fall-off effect. The recommended default value is 1.55.
用来计算菲涅耳效应的折射率，推荐的默认值是1.55。
Transparency
透明度
Color
颜色
This defines the tint color of the transparency.
这定义了透明度的色彩。
Weight
重量
This scales the overall amount of the transparency.
这可以缩放透明度的总量。
Enabling transparency for hair will have a significant impact on performance. It is not recommended.
使头发的透明度对性能有很大的影响，不建议这样做。
Advanced
高级
Balance Diffuse/Reflection Energy
平衡漫反射能量
For physically correct energy conservation, stronger reflections will automatically result in weaker overall diffuse lighting, in order for the material to not reflect more light than it receives.
为了物理上正确的节能，更强的反射会自动导致整体漫射照明较弱，为了使材料不反射比它接收到更多的光。
Disabling this option means the reflection strength will not affect the diffuse lighting strength.
Disabling this option can result in non physically correct lighting, unless the reflection and diffuse weights are carefully balanced by hand.
禁用此选项意味着反射强度不会影响漫射照明强度。禁用此选项可能导致不正确的物理照明，除非反射和漫射权重小心平衡的手。
Enable Trace Depth Overrides
启用跟踪深度重写
This enables the Max Reflection/Refraction Trace Depth parameters. When not enabled, the global trace depths will be used.
这启用了最大反射/折射跟踪深度参数。如果没有启用，将使用全局跟踪深度。
Reflection
反思
Trace Depth
追踪深度
This specifies how many reflection bounces can occur after shading the material. Increasing this can add indirect lighting to thick fur, but will impact rendering time.
这指定了在对材质进行阴影处理之后可以发生多少次反射。增加这个可以增加间接照明厚毛皮，但会影响渲染时间。
Enable Trace Depth Overrides must be enabled for this setting.
必须为此设置启用跟踪深度重写。
Cut-off Override Enable
切断重写启用
This enables the luminance cut-off threshold override, which is used instead of the global threshold.
这将启用亮度截止阈值覆盖，该阈值用于替代全局阈值。
Cut-off Override Threshold
截止覆盖阈值
When the reflected results are very dark (because of low "Weight" or "Color" values) they contribute very little to the final image. This parameter defines what is considered "very dark" at which point no more reflection rays will be shot - which will speed up rendering. Scenes containing very strong lights might need this parameter set to very low values such as 0.0001 in order to avoid early termination of tracing which can produce a grain-like effect.
当反射的结果非常黑暗(因为低的“重量”或“颜色”值) ，他们贡献非常小的最终图像。这个参数定义了什么被认为是“非常黑暗”，在这一点上没有更多的反射射线将被拍摄-这将加速渲染。包含非常强光的场景可能需要将这个参数设置为非常低的值，如0.0001，以避免过早终止跟踪，因为跟踪会产生类似颗粒的效果。
Transparency
透明度
Trace Depth
追踪深度
This specifies the trace depth for transparency rays for this material. Increasing this depth will dramatically impact rendering performance.
这指定了这种材质的透明光线的跟踪深度。增加这种深度将极大地影响渲染性能。
Enable Trace Depth Overrides must be enabled for this setting.
必须为此设置启用跟踪深度重写。
Transparency Cut-off Override Enable
透明度切断重写启用
This enables the luminance cut-off threshold override, which is used instead of the global threshold.
这将启用亮度截止阈值覆盖，该阈值用于替代全局阈值。
Transparency Cut-off Override Threshold
透明度截止重写阈值
When the transparency results are very dark (because of low "Weight" or "Color" values) they contribute very little to the final image. This parameter defines what is considered "very dark" at which point no more reflection rays will be shot - which will speed up rendering. Scenes containing very strong visible lights, or incandescent objects might need this parameter set to very low values such as 0.0001 in order to avoid early termination of tracing which can produce a grain-like effect.
当透明度结果是非常黑暗的(因为低“重量”或“颜色”值) ，他们贡献非常小的最终图像。这个参数定义了什么被认为是“非常黑暗”，在这一点上没有更多的反射射线将被拍摄-这将加速渲染。场景包含非常强的可见光，或白炽物体可能需要这个参数设置为非常低的值，如0.0001，以避免追踪过早终止，可能会产生颗粒状效果。
Combined Trace Depth
组合痕迹深度
This allows you to set a custom combined trace depth for your hair shader.
这允许你为你的头发着色器设置一个自定义的组合跟踪深度。
Enable Trace Depth Overrides must be enabled for this setting.
必须为此设置启用跟踪深度重写。
Hair Example
头发的例子
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| The example above shows a head of hair using the default shader settings, lit by a single dome light. Model courtesy of Emilio Hernandez. 上面的例子显示了一个头发使用默认着色器设置，由一个单一的圆顶灯照明。模型提供: Emilio Hernandez | To demonstrate what each reflection layer looks like, above is the primary reflection only, which contributes to the shininess of the hair. 为了演示每个反射层的样子，上面只是主反射层，这有助于头发的光泽 | Here is the transmission layer, which adds translucency to the hair. 这里是透射层，它增加了半透明的头发 |
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| Here is the internal reflection layer, which determines the overall color of the hair. You may notice a difference in color strength from the first image. This is due to energy preservation, with the primary reflection layer taking away energy from the internal reflection layer. 这是内部反射层，它决定了头发的整体颜色。你可能会注意到第一张图片的色彩强度有所不同。这是由于能量保存，主反射层从内反射层带走了能量 | The image above now has a diffuse color of white added, with a fairly low weight of 0.3. This effectively replaces the internal reflection color and makes the hair look 'powdery'. 上面的图像现在添加了白色的漫反射颜色，重量相当低，只有0.3。这有效地替代了内部反射的颜色，使头发看起来“粉状” |
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