2011

Table Of Contents
Non-Destructive Updates
Pre-comp import updates are completely non-destructive. When an update is
needed on a composition of any type (render layer, render pass, or scene),
modifications are applied to a new version of the composition (if you turned
on the Backup Working Version option in the Pre-Compositing Import Options
dialog box or project preferences), which could be a clone of the working
version or a new version recreated from scratch.
Moreover, when an update is applied on a clone of the working version, none
of the existing nodes in it are deleted (only new content is added) and existing
connections are preserved.
Partial updates are also supported. That is, only some cameras or some render
layers and passes could be modified during a pre-composition update.
A scene, render layer, or render pass composition is not updated if it doesn't
need to be. You can re-export the entire contents of the scene and only the
content that needs to be updated will be.Changing the path or the content
of a pre-compositing template will not trigger an update as the Composite
application does not detect when the template has changed. In this case, you
should use the Recreate Working Version update mode in the Pre-Compositing
Import Options dialog box or project preferences.
Frame Rates
Since Composite does not support all frame rates, there may be cases where
the time units in the 3D application, such as Maya, may correspond to an
unsupported rate in Composite. During import of the pre-comp file, Composite
finds and uses the closest supported rate. However, a warning is displayed
which applies to all types of compositions (render layer, render pass, or scene).
Render Pass Compositions
Render Pass Composition Creation
The render pass image files are imported in a new footage composition. If the
files are in OpenEXR format, the appropriate channels are selected.
The render pass files don't need to be on disk for them to be imported by
Composite in the correct image and pixel format and time range because all
of this information can be queried by Composite through the pre-comp file.
Also, pre-multiplication with the proper background color is handled correctly.
314 | Chapter 13 Pre-Compositing