原理化BSDF
The Principled BSDF that combines multiple layers into a single easy to use node. It can model a wide variety of materials.
It is based on the OpenPBR Surface shading model, and provides parameters compatible with similar PBR shaders found in other software, such as the Disney and Standard Surface models. Image textures painted or baked from software like Substance Painter may be directly linked to the corresponding input in this shader.
层
The base layer is a mix between metal, diffuse, subsurface, and transmission components. Most materials will use one of these components, though it is possible to smoothly mix between them.
The metal component is opaque and only reflect lights. Diffuse is fully opaque, while subsurface also involves light scattering just below the surface. Both diffuse and subsurface sit below a specular layer. The transmission component includes both specular reflection and refraction.
On top of all base layers there is an optional glossy coat. And finally the sheen layer sits on top of all other layers, to add fuzz or dust.
Light emission can also be added. Light emits from below the coat and sheen layers, to model for example emissive displays with a coat or dust.
输入
- 基础色
Overall color of the material used for diffuse, subsurface, metal and transmission.
- 粗糙度
Specifies microfacet roughness of the surface for specular reflection and transmission.
- 金属度
Blends between a dielectric and metallic material model. At 0.0 the material consists of a diffuse or transmissive base layer, with a specular reflection layer on top. A value of 1.0 gives a fully specular reflection tinted with the base color, without diffuse reflection or transmission.
- IOR
Index of refraction for specular reflection and transmission.
- Alpha
控制表面的透明度，数值设定为1.0时，表面完全不透明。通常连接到 "图像纹理" 着色器节点的Alpha输出接口。
- 法向
控制基础图层的法线方向。
次表面
Subsurface scattering is used to render materials such as skin, milk and wax. Light scatters below the surface to create a soft appearance.
- 方法
模拟次表面散射的渲染方式。
- 克里斯坦森-伯利:
基于物理的体积散射的近似值。此方法不如 随机游走 准确，但是，在某些情况下，此方法将更快地解决噪声。
- 随机游走:
Cycles Only Provides accurate results for thin and curved objects. Random Walk uses true volumetric scattering inside the mesh, which means that it works best for closed meshes. Overlapping faces and holes in the mesh can cause problems.
- 随机游走(皮肤):
Cycles Only Random walk method optimized for skin rendering. The radius is automatically adjusted based on the color texture, and the subsurface entry direction uses a mix of diffuse and specular transmission with custom IOR. This tends to retain greater surface detail and color and matches measured skin more closely.
- 权重
Blend between diffuse surface and subsurface scattering. Typically should be zero or one (either fully diffuse or subsurface)
- 半径
光散射到表面下方的平均距离。较高的半径可以使外观更柔和，因为光线会流入阴影区域并穿过物体。散射距离是针对RGB通道单独指定的，对于具有较强红光散射的面板材质，渲染效果较佳。X，Y和Z的数值会分别映射到R，G和B的值。
- 比例|缩放
Scale applied to the radius.
- IOR 仅 Cycles
Index of refraction used for rays that enter the subsurface component. This may be set to a different value than the global IOR to simulate different layers of skin.
- 各向异性 仅Cycles
Directionanltiy of volume scattering within the subsurface medium. Zero scatters uniformly in all directories, with higher values scattering more strongly forward. For example skin has been measure to have an anisotropy of 0.8.
镜面反射
Controls for both the metallic component and specular layer on top of diffuse and subsurface.
- 分布
要使用的微面分布。
- GGX:
A method that is faster than Multiple-scattering GGX but is less physically accurate.
- 多重散射GGX:
Takes multiple scattering events between microfacets into account. This gives more energy conserving results, which would otherwise be visible as excessive darkening.
- 折射率等级
Adjustment to the IOR to increase or decrease intensity of the specular layer. 0.5 means no adjustment, 0 removes all reflections, 1 doubles them at normal incidence.
This input is designed for conveniently texturing the IOR and amount of specular reflection.
- 染色
Color tint for specular and metallic reflection.
For non-metallic tints provides artistic control over the color specular reflections at normal incidence, while grazing reflections remain white. In reality non-metallic specular reflection is fully white.
For metallic materials tints the edges to simulate complex IOR as found in materials such as gold or copper.
- 各向异性过滤 仅适用于Cycles引擎
镜面反射的各向异性量。较高的设定值可提供沿切线方向的细长高光；设定为负值则会给出垂直于切线方向的高光。
- 各向异性旋转 仅适用于Cycles引擎
旋转各向异性的方向，取值为1.0时，旋转一周。
与 各向异性 BSDF 着色器节点不同，该节点的高光延伸方向会旋转90°。可通过增加0.25的旋转值进行更正。
- 切向（正切）
控制 各向异性 图层的法线方向。
透射
Transmission is used to render materials like glass and liquids, where the surface both reflects light and transmits it into the interior of the object
涂层
Coat on top of the materials, to simulate for example a clearcoat, lacquer or car paint.
- 权重
Controls the intensity of the coat layer, both the reflection and the tinting. Typically should be zero or one for physically-based materials, but may be textured to vary the amount of coating across the surface.
- 粗糙度
Roughness of the coat layer.
- IOR
Index of refraction of the coat layer. Affects its reflectivity as well as the falloff of coat tinting.
- 染色
Adds a colored tint to the coat layer by modeling absorption in the layer. Saturation increases at shallower angles, as the light travels farther through the medium, depending on the IOR.
- 法向
Controls the normals of the Coat layer, for example to add a smooth coating on a rough surface.
光泽
Sheen simulates very small fibers on the surface. For cloth this adds a soft velvet like reflection near edges. It can also be used to simulate dust on arbitrary materials.
自发光（发射）
Light emission from the surface.
输出
- BSDF
标准着色器输出。