After Effects Composition Panel

The composition panel is where you preview a comp. Changes made in the timeline are shown here, as well as extra information such as masks, motion paths, etc.

You can also perform certain tasks directly in the window; for example, moving items around or setting coordinate points for effects.

The top of the panel includes the standard CS3 panel features such as a drop-menu for different files, handles for moving the panel, and the flyout menu.

The buttons along the bottom of the panel are described below.

	Always preview this view Use this viewer as the preview, even when changing settings in other panels.
	Magnification ratio Adjusts the zoom level of the image. This only affects your view, not the actual size of the composition. Note: You can also use your mouse wheel to zoom in and out.
	Choose grid and guide options Add and remove guides such as grid, safe areas, etc.
	Toggle mask and shape path visibility Show or hide masks and shape paths.
	Current time Shows the current time position, and allows you to jump to a specified time.
	Take snapshot Takes a snapshot of the current view so you can compare different views.
	Show last snapshot Click and hold to see the last snapshot
	Show channel Show individual color channels (as grayscale) or the alpha channel.
	Resolution/Downsample factor Adjusts the resolution of the preview. This does not affect the composition itself, only the preview image. If your computer is struggling to keep up with previews, reducing the resolution can help.
	Region of interest Allows you to create a region of the image to work on. When activated, only this region is visible — the rest of the image is black. This is useful when you are only working on a small part of the image because the rest of the frame doesn't have to be rendered.
	Toggle transparency grid Turns the checkered transparency grid off and on for transparent areas.
	3D view For working with 3D compositions.
	Select view layout Select the type of view for 3D work.
	Toggle pixel aspect ratio correction Adjusts the preview to compensate for non-square pixels used in some video formats.
	Fast previews Select different preview modes to reduce rendering requirements and work faster.
	Timeline Brings the timeline for the current comp into focus.
	Comp flowchart view Shows the flowchart view.
	Reset exposure Cancels any adjustments made to the preview exposure.
	Adjust exposure Adjust the preview exposure. This changes the exposure of the preview but does not affect the final output (to do that, use the Exposure effect).

Notes:

• You can have multiple compositions open in the composition panel. Switch between them using the drop-menu at the top of the panel.
• You can have more than one composition panel visible. In the drop-menu, select New Comp Viewer. You can move and arrange the new panel(s) just like any other panel.