Saving Time By Prerendering Nested Compositions; To Use The Pre-Render Command; To Edit A Prerendered Composition - Adobe AFTER EFFECTS 7.0 Manual

Collapsing transformations also adds some flexibility when you work with 3D layers in nested compositions. If you
have a subordinate composition that has 3D objects within it without turning on Collapse Transformations, After
Effects renders the composition as a 2D image of the 3D arrangement in the next higher composition. However, if
you turn on Collapse Transformations, After Effects renders the 3D layers into the next higher composition so that
they retain their 3D relationships among themselves and with other 3D layers there. You can continue to manipulate
the relative positions of the 3D layers as a group from the lower composition.
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In the Layer Switches column of the Timeline panel, click the Collapse Transformations switch icon
layer containing the nested composition.
Note: When you enable the Collapse Transformations switch for a nested composition, guide layers in the nested compo-
sition will no longer display.

Saving time by prerendering nested compositions

A complex nested composition can take a long time to preview and render. If you have a nested composition that you
do not expect to work on any further, render the nested composition into a movie and use it as a proxy for the actual
nested composition. As a rendered movie, it will require less calculation and will take less time to display and render
in the larger project. You can still make changes to the prerendered composition, because the original nested compo-
sition remains in the project list. If you make a significant change to the original nested composition, simply render
it again. Prerendering a nested composition is particularly beneficial when you use a nested composition multiple
times in a project.
Using a prerendered movie in place of a nested composition also saves time and memory when you render the final
version of the main composition. Just be sure to apply your final output settings when you prerender the nested
composition.
There are three phases to prerendering a composition: Creating a composition, rendering the composition you
created, and then creating a proxy from the rendered composition. Use the Pre-render command to automate the
last two phases.
See also
"To change render settings" on page 604

To use the Pre-render command

The Pre-render command provides an easy way to flatten nested compositions, greatly shortening preview times.
The command opens the render queue and creates a render item for the selected composition with Import and
Replace Usage selected as the Post-Render Action option.
Select the composition in the Project or Composition panel.
1
2 Choose Composition > Pre-render. Adjust the settings as necessary, and render the footage.

To edit a prerendered composition

1 In the Project panel, click the proxy indicator
This turns off the proxy so that After Effects uses the actual composition in the project.
In the Project panel, double-click the composition from which the proxy movie was rendered.
2
Edit the composition.
3
Save the project.
4
for the prerendered composition until it displays an empty box.
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