Adobe After Effects CS3 - Manual (Page 495)

AFTER EFFECTS CS3
User Guide
490
Original (top left), and with Bottom set to the text layer (bottom left) and Water Surface set to the whirl layer with Surface Opacity set to 0%
(bottom right)
To get the most realistic results from Caustics, render the Bottom layer separately, with Render Caustics enabled and
Surface Opacity at 0. Then precompose, and use the resulting layer as the Bottom layer for another Caustics effect
with Render Caustics off. With this process you can offset, scale, or otherwise manipulate the Bottom layer in the precom-
posed composition, and thus simulate lighting that doesn’t come from straight overhead.
See also
“Common Lighting controls and Material controls” on page 486
Bottom controls
The Bottom controls specify the appearance of the bottom of the body of water:
Bottom Specifies the layer at the bottom of the body of water. This layer is the image that is distorted by the effect,
unless Surface Opacity is 100%.
Scaling Makes the bottom layer larger or smaller. If the edges of the bottom layer show, because of the refraction of
the light through the waves, scale up the bottom layer. Scaling down is useful for tiling a layer to make a complex
pattern.
Repeat Mode Specifies how a scaled-down bottom layer is tiled. Once uses only one tile, basically turning tiling off.
Tiles uses the traditional tiling method of abutting the right edge of one bottom layer tile to the left edge of another
bottom layer tile. This option works well if the bottom layer contains a repeating pattern, like a logo, that needs to
read a certain way. Reflected abuts each edge of a bottom layer tile to a mirrored copy of the tile. This option can
eliminate a hard edge where the two tiles meet.
If Layer Size Differs Specifies how to handle the bottom layer when it is smaller than the composition.
Blur Specifies the amount of blur applied to the bottom layer. To make the bottom totally sharp, set this control to
0. Higher values make the bottom appear increasingly blurry, especially where the water is deeper.
Water controls
Water Surface Specifies the layer to use as the water’s surface. Caustics uses the luminance of this layer as a height
map for generating a 3D water surface. Light pixels are high, and dark pixels are low. You can use a layer created by
using the Wave World or Radio Waves effect; precompose the layer before using it with Caustics.
Wave Height Adjusts the relative height of the waves. Higher values make the waves steeper and the surface
displacement more dramatic. Lower values smooth the Caustics surface.