Adobe After Effects CS3 - Manual (Page 176)

AFTER EFFECTS CS3
User Guide
171
Exclude channels from blending
You can exclude one or more of a layer’s color channels from blending operations.
The Blending Options property group is only included for a layer if the layer has had a layer style added to it. To add
a Blending Options property group without a layer style, add an arbitrary layer style and then immediately delete it;
the Blending Options property group and its containing Layer Styles property group will remain.
1 Expand the layer’s Blending Options property group in the Layer Styles property group in the Timeline panel.
2 To exclude a channel from blending, set Red, Green, or Blue to Off in the Advanced Blending property group.
You can animate these properties, so you can exclude a channel from blending at some times but include the channel
at other times.
Working with 3D layers
About 3D layers
The basic objects that you manipulate in After Effects are flat, two-dimensional (2D) layers. When you make a layer
a 3D layer, the layer itself remains flat, but it gains additional properties: Position (z), Anchor Point (z), Scale (z),
Orientation, X Rotation, Y Rotation, Z Rotation, and Material Options properties. Material Options properties
specify how the layer interacts with light and shadows. Only 3D layers interact with shadows, lights, and cameras.
2D layers (left) and layers with 3D properties (right)
Any layer can be a 3D layer, except an audio-only layer. Individual characters within text layers can optionally be 3D
sublayers, each with their own 3D properties. A text layer with Enable Per-character 3D selected behaves just like a
precomposition that consists of a 3D layer for each character. All camera and light layers have 3D properties.
By default, layers are at a depth (z-axis position) of 0. In After Effects, the origin of the coordinate system is at the
upper-left corner; x (width) increases from left to right, y (height) increases from top to bottom, and z (depth)
increases from near to far. Some video and 3D applications use a coordinate system that is rotated 180 degrees
around the x axis; in these systems, y increases from bottom to top, and z increases from far to near.
You can transform 3D layers relative to the composition’s coordinate space, the layer’s coordinate space, or a custom
space by selecting an axis mode.
You can add effects and masks to 3D layers, composite 3D layers with 2D layers, and create and animate camera and
light layers to view or illuminate 3D layers from any angle.
All effects are 2D, including effects that simulate 3D distortions. This means that, for example, viewing a layer with
the Bulge effect from the side will not show a protrusion.
As with all masks, mask coordinates on a 3D layer are in the 2D coordinate space of the layer.