Adobe After Effects CS4 - Manual (Page 440)

434 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
More Help topics
“ About 3D Channel effects ” on page 430
“ Preparing and importing 3D image files ” on page 98
“ 3D layers ” on page 179
Fog 3D effect
The Fog 3D effect simulates fog by behaving as though a scattering medium is in the air that makes objects look more
diffuse as they get more distant along the z axis.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Note: As with all effects in the 3D Channel effects category, the Fog 3D effect depends on depth information from image
sequence files of the kind rendered out of a 3D application. For general information on 3D Channel effects, see “
About
3D Channel effects ” on page 430. For information about simulating fog in After Effects, see “ Fog, smoke, clouds ” on
page 33.
Original (upper-left), Gradient Layer (lower-left), and with Fog 3D applied (lower-right)
Fog Start Depth Where along the z axis the diffuse scattering begins.
To determine the depth of an object, click it in the Composition panel or Layer panel using the Selection tool while the
effect is selected.
Fog End Depth Where along the z axis the diffusion reaches its maximum.
Scattering Density Determines how quickly the scattering occurs. The higher the value, the more dense the fog
appears from its starting point.
Foggy Background Creates a foggy background (default). Deselect to create transparency at the back of the 3D scene
for compositing on top of another layer.
Gradient Layer (Optional) A grayscale layer to use as a control layer, the luminance values of which apply to fog
density. For example, use the Turbulent Noise effect to create a swirling control layer for atmospheric fog. Make sure
that the dimensions of the gradient layer are at least as great as the dimensions of the 3D scene layer.
Layer Contribution How much the gradient layer affects the fog density.