User Guide

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Chapter 9: 3D Compositing
he ability to work with layers in three dimensions, or 3D, allows you to add true
depth to animations. By combining this depth with a variation of lights and camera
angles, you create projects that take advantage of the full range of natural motion,
lighting and shadows, perspective, and focusing effects.
In After Effects, you can add 3D properties to almost any layer. In addition to being able
to adjust the depth variables that are added to the layer transform properties, you can also
add effects and masks to 3D layers and combine 3D with traditional 2D layers.
Understanding 3D
Many graphics programs, including After Effects, display images in two dimensions, or
2D, which means that these images exist in and can only be moved to locations along the
horizontal (X) and vertical (Y) axes.
A conventional After Effects 2D image (left) and an image with 3D properties (right).
Programs that work in 3D add distance, or depth, as another dimension in which an
element of the image, or object, can be placed. Depth is expressed as an additional
coordinate, called “Z.” As with X and Y coordinates, the Z coordinate defines the position
of an object along the depth axis, called the Z axis. 3D coordinates are expressed as the
variable (x, y, z). A positive Z coordinate indicates that an image is located farther from the
viewer; a negative Z coordinate indicates that an image is nearer to the viewer. Adding
depth allows objects to display more realistic depictions of how they reflect light, cast
shadows, and move through space.
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UG.book Page 283 Wednesday, February 21, 2001 12:05 PM