次表面散射 (SSS)

次表面散射 节点用于为诸如皮肤，蜡，大理石，牛奶等材质添加简单的次表面多次散射效果。对于上述材质，光线不会直接从表面反射，而是会穿透表面并在内部反弹，然后被吸收或离开表面到达附近的点。

可以根据RGB颜色通道配置颜色散布的平均距离。例如，对于皮肤，红色会进一步散射，从而产生独特的红色阴影和柔和的外观。

输入

颜色: 物体表面的颜色，从物理学角度讲，既光线中的不同波长被反射的概率。
比例|缩放: 散射半径的全局全局缩放系数。
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皮肤材质，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。
IOR Cycles Only: Index of refraction for Subsurface Scattering.
Anisotropy Cycles Only: Controls the directionality of subsurface scattering.
法向: 用于着色的法向；如果没有连接其它选项，则使用默认着色法向。

次表面方法

模拟次表面散射的渲染方式。

Note

Eevee does use not support the Random Walk methods.

克里斯坦森-伯利: An approximation to physically-based volume scattering. This method is less accurate than Random Walk however, in some situations this method will resolve noise faster.
Random Walk (Fixed Radius): 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: Behaves similarly to Random Walk (Fixed Radius) but modulates the Radius based on the Color, Anisotropy, and IOR. This method thereby attempts to retain greater surface detail and color than Random Walk (Fixed Radius).