Redshift Light

Redshift supports most of the native light types in Autodesk Maya and Softimage as well as a number of Redshift-specific light types.
Redshift 撑持大部门Maya或者Softimage的原生灯光类型，也有本人的灯光类型。

Topics in this section
1、Native Maya Lights      Maya的原生灯光
2、Redshift Lights              Redshift灯光


Native Maya Lights Maya原生光源

Lights光源

The following standard Maya light types are supported by Redshift:Redshift撑持下列Maya原生光原类型：
1、Directional Light 标的目的光
2、Point Light点光
3、Spot Light聚光灯
4、Area Light面积光.


Note 注意
Ambient Light and Volume Light are not supported by Redshift.
Redshift不撑持Area Light(环境光)和Volume Light(体积光)。
The following light attributes are not applicable to Redshift or not currently supported by Redshift:
以下光源属性Redshift目前不撑持：
1、Illuminates by Default (All)         Default Light（所有参数）


2、Dropoff衰减(Spot)
3、All attributes under the Light Effects group (Point, Spot, Area)
4、Lighit Effects下的所有参数（Point、Spot、Area）


5、All attributes under the Shadows > Depth Map Shadow Attributesgroup (All)
6、Shadows>Depth Map Shadow Attributes下面的所有属性（ALL）
7、Ray Depth Limit (All)
8、Ray Depth Limit采样Trace Depth限定（All）


9、All attributes under the mental ray group – Redshift equivalents for relevant attributes are under the Redshift group
10、Mental Ray下的所有属性----相应的属性在Redshift组别下面


Certain light attributes are only partially supported by Redshift or may behave differently when compared to Mental Ray.
一些灯光属性Redshift只是部门撑持，而且有可能与Mental Ray中的效果不同。

Decay Rate 衰减率
Redshift only supports No Decay and Quadratic. 只撑持不衰减和平方衰减



edshift Attributes   Redshift属性

Redshift automatically adds a number of attributes to native Maya lights.
Redshift主动为Maya原生光原添加大量属性。


Area Lighting (Area Lights Only) 区域照明（只撑持Area Lights）




Shape外形
Specifies the physical shape of the area light. 指定Area Light的物理外形
RectangleDiscSphere 长方形
Cylinder 圆柱形
Visible可见
Makes the area light visible to the camera (and through reflections and refractions).
使面积光源在渲染中间接可见（搜罗出如今反射和折射中）
Samples采样
Specifies the number of ray samples to use for the area light.  More samples will produce smoother lighting and shadows.  Generally, the larger and more intense an area light is, the more samples it needs to produce noise-free results.
为此面积光源指定采样射线的数量。更多的采样为使光照和阴影成果更平滑。通常，面积光源越大或是越亮，就越是需要更多的采样来产生无噪的效果。

Photons (All Lights)   光子（所有灯光）


Emit Caustic Photons
发射焦散光子
Enables caustic photon casting for the light.  Has no effect if Enable Caustics is not enabled in the Redshift Render Options under the Photon Mapping tab.
允许光源发射焦散光子投射。假如在Redshift Render Options中Photon Mapping选项卡下的Enable Caustics并未被启用，则无效。
Emit GI Photons
发射GI光子
Enables GI photon casting for the light.  Has no effect if Enable GI is not enabled in the Redshift Render Options under the Photon Mapping tab.
允许光源发射GI光子。假如在Redshift Render Options中Photon Mapping选项卡下的Enabled GI并未被启用，则无效。
Caustic Photons
焦散光子
Specifies the number of caustic photons to shoot for the light.
指定要从光源发射的焦散光子数量
GI Photons
GI光子
Specifies the number of GI photons to shoot for the light.
指定要从光源发射的GI光子数量
Photon Color
光子颜色
Specifies the color of caustic and GI photons emitted by the light.
指定光源发出的Caustics光子和GI光子的颜色。
Photon Intensity
光子强度
Specifies the intensity of caustic and GI photons emitted by the light.
指定光源发出的Caustics光子的GI光子强度。

Light Shaders (All Lights)光源节点接口（All Light）


Light Shader
光源节点
Specifies a connection to a light shader.  Redshift will execute a connected light shader to compute the light intensity and color as well as the shadow color from a given point on a surface.
用于连接一下Light Shader。Redshift在计算外表上某一点的光影时，将通过连接的Light Shader计算光源的强度、颜色和阴影。
Photon Shader
光子节点
Specifies a connection to a photonshader.  Redshift will execute a connected photon shader to control the emission of photons from the light.
用于连接一个Photon Shader。Redshift将从此端口连接的Photon Shader发射光子。

Light Shaders

When using Mental Ray in Maya, light shaders can be connected to lights to change their behavior.
Maya中使用Mental Ray时，Light shader连接到光源后，将改变光源的性质。
Redshift translates Maya lights and associated light shaders into their Redshift equivalents allowing you to use most of the native Maya light features with Redshift directly.  Note however that certain light shaders and/or light shader parameters are unsupported or only partially supported by Redshift.  We therefore recommend using Redshift lights instead of the native Maya lights whenever possible.
通过将Maya光源以及所连接的Light Shader转换成本人的对应光源，Redshift能够撑持绝大部门Maya原生光源。但是请注意，但是请注意，这些光源以及它们的参数只是部门被撑持。因而建议还是应该尽可能的使用Redshift提供的光源。


Supported Light Shaders撑持的光源节点

The following lists the Mental Ray for Maya light shaders that Redshift supports at least partially:
以下列出了Redshift部门撑持的Mental Ray for Maya光源节点：
mia_photometric_light
mia_physicalsun
mia_portal_light
mib_blackbody
mib_cie_d

Unsupported or Partially Supported Light Shaders 不撑持或者仅部门撑持的光源节点

The following describes the Mental Ray for Maya light shaders and parameters which are not supported or only partially supported by Redshift with notes where applicable.
以下列出了Redshift不撑持或者部门撑持的Mental Ray for Maya光源节点的参数。撑持的部门配以文字说明。
mia_photometric_light
units_to_meter_scale
单元尺寸
The unit scale for Redshift is defined globally in the Redshift Render Options under Output > Photometric Units > Units To Meters Scale.
Redshift单元定义是全局参数，定义在Redshift渲染设置下的Output > Photometric Units > Units To Meters Scale.
cm2_factor
亮度系数
The candela per meter square factor for Redshift is defined globally in the Redshift Render Options under Output > Photometric Units >cd/m^2 Factor.
Redshift坎德拉/每平方亮度系数是全局参数，定义在Redshift渲染设置下的Output > Photometric Units >cd/m^2 Factor.

mia_physicalsun
photon_bbox_min
Not supported. 不撑持
photon_bbox_max
Not supported. 不撑持
illuminance_mode
Not supported. 不撑持
direct_normal_illuminance
Not supported. 不撑持

mia_portal_light
cutoff_threshold
Not supported. 不撑持
shadow_ray_extension
Not supported. 不撑持
use_custom_environment
使用自定义环境
A custom environment shader will always be used if it is connected to the custom_environment input, regardless of the value of Use Custom Environment Shader.
只要环境节点被连接在Custom_environment输入端口上，无论能否开启使用自定义环境，自定义环境城市起做用。
lookup_using_fg_rays
Not supported. All environment maps will be treated as if sampled by GI rays, in order to correctly support Multiple Importance Sampling.
不撑持。为了撑持Multiple Importance Sampling（多权重采样），所有环境贴图城市被 GI射线采样。

mib_fg_occlusion

The mib_fg_occlusion light shader is not currently supported. 该光源节点目前不撑持
mib_light_infinite

The mib_light_infinite light shader is not currently supported. 该光源节点目前不撑持
mib_light_photometric

The mib_light_photometric light shader is not currently supported. 该光源节点目前不撑持
mib_light_point

The mib_light_point light shader is not currently supported. 该光源节点目前不撑持
mib_light_spot

The mib_light_spot light shader is not currently supported. 该光源节点目前不撑持
physical_light

The physical_light light shader is not currently supported. 该光源节点目前不撑持


Common Redshift Light Parameters通用Redshift光源参数

All Redshift lights share common parameters related to photon emission.
所有的Redshift光源都有光子相关的属性。

Photon光子



Caustics焦散

Emit Caustic Photons
开启Caustic光子
Enables caustic photon casting for the light.  Has no effect if Enable Caustics is not enabled in the Redshift Render Options under the Photon Mapping tab.
为灯光开启Caustics光子。假如没有开启渲染选项的Photon Mapping下的Caustics，则没有效果。
Intensity Multiplier
强度倍增器
Specifies a multiplier for the caustic photon intensity, relative to the intensity of the light.  A value of 1 will cause the emitted photons have the same intensity as the light.  Smaller values will yield photons with relatively less intensity than the light, while larger values will yield photons with relatively more intensity.
给Caustics光子强度添加一个倍增选项，关联到灯光的强度，值为1意味着发射的光子强度和灯光强度一样，小的值缩减光子强度，大的值加强光子强度。
Number of Photons to Emit
发射光子数量
Specifies the number of caustic photons to shoot for the light.
定义发射Caustics光子的数量。

GI

Emit GI Photons
发射GI光子
Enables GI photon casting for the light.  Has no effect if Enable GI is not enabled in the Redshift Render Options under the Photon Mapping tab.
为灯光开启GI光子。假如没有开启渲染选项Photon Mapping下的GI，则没有效果。
Intensity Multiplier
强度倍增器
Specifies a multiplier for the GI photon intensity, relative to the intensity of the light.  A value of 1 will cause the emitted photons have the same intensity as the light.  Smaller values will yield photons with relatively less intensity than the light, while larger values will yield photons with relatively more intensity.
给GI光子强度添加一个倍增选项，关联到灯光的强度，值为1意味着发射的光子强度和灯光强度一样，小的值缩减光子强度，大的值增加光子强度。
Number of Photons to Emit
发射光子数量
Specifies the number of GI photons to shoot for the light.
定义发射GI光子的数量