Adobe 65008009 - After Effects CS4 Using Manual page 382

Last updated 12/21/2009
The position of a mask in the stacking order in the Timeline panel affects how it interacts with other masks. You can
drag a mask to different positions within the Masks property group in the Timeline panel.
The Mask Opacity property for a mask determines the influence that a closed mask has on the alpha channel of the
layer inside the mask area. A Mask Opacity value of 100% corresponds to an interior area that is completely opaque.
The area outside the mask is always completely transparent. To invert what is considered inside and what is considered
outside for a specific mask, select Invert next to the mask name in the Timeline panel.
Trish and Chris Meyer provide an introduction to masks in a PDF excerpt from the "Creating Transparency" chapter
of their book After Effects Apprentice: Real-World Skills for the Aspiring Motion Graphics
More Help topics
"Creating shapes and masks" on page 312
Copy, cut, save, reuse, and delete masks
You can reuse masks in other layers and compositions, which is especially useful for Bezier masks you've spent a long
time perfecting. Mask paths are stored inside a composition in a project file.
More Help topics
"Creating shapes and masks" on page 312
"Managing and animating shape paths and
Copy, cut, duplicate, or paste a mask
Note: When working with a mask path—rather than the entire mask, including its other properties—select the Mask Path
property. This is especially important when transferring mask paths to shape paths, motion paths, and so on.
• To copy or cut selected masks to the clipboard, choose Edit > Copy or Edit > Cut.
• To duplicate selected masks, choose Edit > Duplicate.
• To paste a mask onto a layer, select the layer and then choose Edit > Paste. If a mask is selected, this operation
replaces the selected mask.
Save a mask
In the Timeline panel for the composition containing the layer and mask you want to save, expand the layer and its
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mask properties.
Do one of the following:
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• To save an animated mask, select the mask keyframes you want to save.
• To save a nonanimated mask, select the mask.
3 Copy the mask or keyframes, and paste the mask or keyframes to a new layer. The new layer can be a simple solid.
Create a project with compositions just for storing complex masks. When you want to use a mask from another
project, import that project into your current project.
Note: You can also save masks as animation presets. (See
Reuse a mask
Open the composition containing the mask you want to reuse. If you saved the mask in another project, import the
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project and then open the composition containing the mask.
masks" on page 322
"Animation presets overview and
USING AFTER EFFECTS CS4
Transparency, opacity, and compositing
Artist.
resources" on page 387.)
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