Adobe After Effects CS4 - Manual (Page 587)

581 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
To understand how this effect works, consider the following information about the physics of waves: A wave consists
of a peak and a trough. The amplitude of a wave is the height, or distance, between the peak and trough. The
wavelength is the distance from one peak to the next. Frequency is the number of waves per second passing a fixed
point.
View controls
View controls specify the method used to preview the Wave World effect. Choose one of the following views:
Height Map Displays the highest points as bright pixels and the lowest points as dark pixels. Use this view when
creating a displacement map.
Wireframe Preview Provides a visual depiction of how the wave is being created. The grayscale output represents a
height map: White represents the highest possible wave, and black represents the lowest. The two rectangular outlines
represent these two extremes: The cyan rectangle represents pure white, and the violet rectangle represents pure black.
The green grid represents the ground layer; it is flat by default but can be distorted by using a grayscale image. The
white grid represents the surface of the water.
Wireframe controls
Wireframe controls fine-tune the appearance of the wireframe model. These controls don’t affect the grayscale output.
Horizontal Rotation Rotates the wireframe preview around the horizontal axis (right and left). As you adjust this
control, the distortion of the wireframe model keeps the entire wireframe model in full view.
Vertical Rotation Rotates the wireframe preview around the vertical axis (up and down).
Vertical Scale Distorts the wireframe preview vertically so that you can see heights more easily. It doesn’t affect the
grayscale output.
Height Map controls
Height Map controls specify the appearance of the height map.
Note: While adjusting Brightness and Contrast, keep the wave surface layer between the cyan and violet rectangles. If a
peak pokes through the cyan rectangle, it clips at pure white. If a trough pokes through the bottom of the violet rectangle,
it clips at pure black. If you want to create a displacement map, try to avoid clipping because it shows up as flat peaks and
valleys, which look unnatural.
Brightness Adjusts the overall height of the water surface. Adjusting it brightens or darkens the overall grayscale
output. If you use Wave World for displacement, this control moves the surface of the water up or down.
Contrast Changes the difference between the grays of the peaks and troughs, making the difference more or less
extreme. Lower values even out the grays, and higher values create a wider range from black to white (until clipping
occurs).
Gamma Adjustment Controls the slope of the waves in relation to the Brightness. Results are visible only in Height
Map view. Higher values result in rounder peaks and narrower valleys, while lower values result in smoother valleys
and pointier peaks.
Render Dry Areas As Specifies how the water surface is rendered when a dry area exists. Dry areas are created when a
portion of the ground layer rises above the surface of the water. You can manipulate the dry area by using the Steepness
control.
This control is useful for compositing a Wave World effect into a scene. For example, you can use a precomposed
Wave World scene with transparency as a displacement map for the Caustics effect, and as a track matte for the effect
layer.