3D layers have Material Options properties, which determine how a 3D layer interacts with light and shadow.
只有3d图层才有材质选项，它决定了3d层如何与灯光和阴影相互作用
Casts Shadows 投影
Specifies whether a layer casts shadows on other layers. The direction and angle of the shadows are determined by the direction and angle of the light sources. Set Casts Shadows to Only if you want the layer to be invisible but still cast a shadow.
指定图层是否将投影投射于其他图层上。投影的方向和角度取决于灯光的方向和角度。如果你希望图层不可见但仍然投射阴影，请将“set cast shadows”属性设置为“only”
Light Transmission 透光率
The percentage of light that shines through the layer, casting the colors of the layer on other layers as a shadow. 0% specifies that no light passes through the layer, casting a black shadow. 100% specifies that the full values of the colors of the shadow-casting layer are projected onto the layer accepting the shadow.
光透过图层的百分比即为透光率，将图层的颜色投射于其他图层上作为阴影。0表示没有光透过图层，投射黑色阴影。100表示将投影图层中所有的色值投射到接受阴影的图层上。
Accepts Shadows 接受阴影
Specifies whether the layer shows shadows cast on it by other layers. In After Effects CS6, an “Only” option is available in Accepts Shadows for when you want to render only a shadow on a layer.
指定图层是否显示来自于其他图层的投影。在cs6版本中，可以选择only来实现图层仅渲染阴影。
Accepts Lights 接受灯光
Specifies whether the color of a layer is affected by light that reaches it. This setting does not affect shadows.
指定图层中的颜色是否受到灯光的影响，该选项不会影响阴影。
Ambient 环境
Ambient (nondirectional) reflectivity of the layer. 100% specifies the most reflectivity; 0% specifies no ambient reflectivity.
图层的环境反射率。100%表示最大反射率，0表示没有环境反射。
Diffuse 漫射
Diffuse (omnidirectional) reflectivity of the layer. Applying diffuse reflectivity to a layer is like draping a dull, plastic sheet over it. Light that falls on this layer reflects equally in all directions. 100% specifies the most reflectivity; 0% specifies no diffuse reflectivity.
图层的慢反射率。将漫反射应用到图层上相当于将一个暗色的塑料片铺到图层上。该图层上的光照会向各方向均匀反射。100%表示最大反射率，0表示没有漫反射。
Specular 镜面
Specular (directional) reflectivity of the layer. Specular light reflects from the layer as if from a mirror. 100% specifies the most reflectivity; 0% specifies no specular reflectivity.
图层的镜面反射率。从图层反射镜面光就像从镜子中反射一样。100%表示最大反射率。0代表没有反射。
Shininess 发光度
Determines the size of the specular highlight. This value is active only if the Specular setting is greater than zero. 100% specifies a reflection with a small specular highlight. 0% specifies a reflection with a large specular highlight.
决定镜面高光的尺寸。该数值仅在镜面参数大于0的情况下才会生效。100%表示反射产生一个较小的镜面高光。0表示产生一个较大的镜面高光。
Metal 金属
The contribution of the layer color to the color of the specular highlight. 100% specifies that the highlight color is the color of the layer. For example, with a Metal value of 100%, an image of a gold ring reflects golden light. 0% specifies that the color of the specular highlight is the color of the light source. For example, a layer with a Metal value of 0% under a white light has a white highlight.
图层颜色对镜面高光所产生的影响程度。100%表示高光颜色为图层颜色。例如metal值为100%，一张金色戒指会反射出金色的光。0代表镜面高光的颜色为光源颜色。例如，一张位于白色灯光下metal值为0的图层会产生白色的高光。
