Adobe After Effects CS4 User Manual
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USING AFTER EFFECTS CS4
Layers and properties
Last updated 12/21/2009
If you use Brainstorm on a single one-dimensional property (such as Opacity, but not Position), the Randomness value
that controls the amount of variation (mutation) is replaced by a Spread value. The variants that are presented in the
Brainstorm dialog box are then not random, but represent a range of values around the central value. The original
composition appears in the center tile of the dialog box, and you can only select one variant on which to base the next
Brainstorm operation.
Though you can’t directly use Brainstorm on expressions, you can use Brainstorm on the properties of Expression
Control effects, to which expressions can refer.
1
Set a work area and region of interest for the duration and spatial area of the composition that you want to preview
during the Brainstorm session. (See “
2
Select one or more properties or property groups in the Timeline panel, and click the Brainstorm button
at the
top of the Timeline panel.
The variant compositions all play in the Brainstorm dialog box simultaneously. Controls for each variant are only
visible when the pointer is over it. Use the playback controls at the bottom of the Brainstorm dialog box to play, pause,
or rewind the previews.
3
In the Brainstorm dialog box, do any of the following:
•
To get a better look at a variant, click its Maximize Tile
button. Click the Restore Tile Size
button to return
to the grid view of all variants.
•
To show or hide the transparency grid, click the Toggle Transparency Grid
button at the bottom of the
Brainstorm dialog box.
•
To mark a variant for inclusion in the next Brainstorm operation, click the Include In Next Brainstorm
button
for that variant.
•
To save a variant as a new composition in the current project, click the Save As New Composition
button for
that variant.
•
To increase the randomness or spread for the next generation, adjust the Randomness or Spread value at the bottom
of the Brainstorm dialog box. Make this number small for precision work; make it larger for experimentation and
exploration.
4
(Optional) To create another generation of variants from the variants marked for inclusion in the next Brainstorm
operation, click Brainstorm at the bottom of the Brainstorm dialog box and return to step 2. If you click Brainstorm
without marking any variants for inclusion, the Brainstorm operation is repeated using the same input as the
current generation.
If the Brainstorm operation uses Randomness, the variants marked for input into the next generation are included
unchanged into the next generation, and remain in their positions in the dialog box. If the Brainstorm operation uses
Spread, only one variant is carried into the next generation, and it appears in the center tile.
Repeat this cycle until you have found the variant that you want to save as the current composition.
You can move back or forward a generation by clicking the arrow buttons on either side of the Brainstorm button at
the bottom of the Brainstorm dialog box. If you move back a generation and then perform another Brainstorm
operation, the later generations are lost.
Note: Press Esc to close the Brainstorm dialog box.
Note: If you use the Save As New Composition feature and the current composition contains expressions that refer to
itself using the
comp("
format, then the saved compositions’ expressions will refer to the original composition,
not each saved composition. If your expression needs to rely on the settings in its own composition, use the
thisComp
object instead.