Adobe After Effects CS3 - Manual (Page 186)

AFTER EFFECTS CS3
User Guide
181
Material Options properties
3D layers have Material Options properties, which determine how a 3D layer interacts with light and shadow.
Casts Shadows 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.
Use the Only setting and a non-zero Light Transmission setting to project the colors of an invisible layer onto another
layer.
Light Transmission The percentage of light that shines through the layer, casting the layer’s color on other layers as
a shadow. 0% specifies that no light passes through the layer, casting a black shadow. 100% specifies that the full color
value of the shadow-casting layer is projected onto the layer accepting the shadow.
Use partial light transmission to create the appearance of light passing through a stained glass window.
Accepts Shadows Specifies whether the layer shows shadows cast on it by other layers.
Accepts Lights Specifies whether the color of a layer is affected by light that reaches it. This setting does not affect
shadows.
Ambient Ambient (nondirectional) reflectivity of the layer. 100% specifies the most reflectivity; 0% specifies no
ambient reflectivity.
Diffuse 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 reflec-
tivity; 0% specifies no diffuse reflectivity.
Specular 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.
Shininess 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.
Metal 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.
See also
“Working with 3D layers” on page 171
“Create a light and change settings” on page 178
Specify resolution to use for rendering shadows
The Advanced 3D rendering plug-in is used to render compositions containing intersecting 3D layers. To render
shadows, the plug-in uses shadow maps, which are images rendered from the point of view of each light source.
Normally, a shadow’s resolution is computed automatically based on the composition resolution and the layers’
quality settings. If normal resolution doesn’t create the quality you want, or renders too slowly, you can adjust the
shadow map resolution. For example, if shadows are blurry and the Shadow Diffusion material option is set to 0,
increase the shadow map resolution. Or, if shadows render too slowly, decrease the shadow map resolution.