Adobe After Effects CS3 - Manual (Page 116)

AFTER EFFECTS CS3
User Guide
111
Start Timecode or Start Frame Timecode or frame number assigned to the first frame of the composition. This value
does not affect rendering; it merely specifies where to start counting from.
Advanced composition settings
For information on specific Advanced composition settings not listed here, see the related sections.
Anchor Click an arrow button to anchor layers to a corner or edge of the composition as it is resized.
Work with the region of interest
The region of interest is the area of the composition, layer, or footage item that is previewed. Create a smaller region
of interest to use less processing power and memory when previewing, thereby improving interaction speed and
increasing RAM preview duration. Changing the region of interest does not affect file output, though you can change
the size of your composition and select what portion is rendered by cropping to the region of interest.
Note: When the region of interest is selected, the Info panel displays the horizontal and vertical distances of the top (T),
left (L), bottom (B), and right (R) edges of the region from the top-left corner of the composition.
• To draw a region of interest, click the Region Of Interest button at the bottom of the Composition, Layer, or
Footage panel, and then drag to select a viewable area of the panel.
To start over with the marquee tool, hold down Alt (Windows) or Option (Mac OS) and click the Region Of Interest
button.
• To switch between using the region of interest and using the full composition, layer, or footage frame, click the
Region Of Interest button.
• To move or resize the region of interest, drag its edges or handles. Shift-drag a corner handle to resize while
preserving aspect ratio.
• To crop to the region of interest, choose Composition > Crop Comp To Region Of Interest.
Set composition background color
The default background color for the Composition panel is black, but you can change the color at any time.
❖ Choose Composition > Background Color, and then click the color swatch or use the eyedropper to pick a color.
Note: When you add one composition to another (nesting), the containing composition’s background color is preserved,
and the nested composition’s background becomes transparent. To preserve the nested composition’s background color,
create a solid-color layer to use as a background layer in the nested composition.
See also
“Select a color or edit a gradient” on page 236
“Create or modify a solid-color layer” on page 136
Work with composition thumbnail images
You can choose which frame of a composition to show as a thumbnail image in the Project panel. By default, a
composition’s thumbnail image is the first frame of the composition, with transparent portions shown as black.
• To set the thumbnail image for a composition, move the current-time indicator to the desired frame in the compo-
sition’s Timeline panel, and choose Composition > Set Poster Time.
• To add a transparency grid to the thumbnail view, choose Thumbnail Transparency Grid from the Project panel menu.