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If some render layer anchor link nodes are missing in the scene template, new
unconnected render layer link nodes are automatically added to the scene
composition (in the same way as when no template is specified).
Without a Template If no scene template is specified, render layer anchor
link nodes are created with their proper anchor name set and point to their
respective render layer composition. Render layers are then stacked in a chain
of Blend and Comp nodes, respecting the compositing order and blend modes
used in the 3D scene.
What Happens Next? The render layer link nodes have their anchors
automatically set to their corresponding render layer anchor name and the
nodes are initially named after their linked render layer compositions (their
names are not changed by further updates).
The image format, pixel format, and the rate of the scene composition are
then set according to the default render settings of the 3D scene. The time
range (start, end) of the scene composition is then set to the union of its render
layer compositions time ranges.
Scene Composition Update
A scene composition is updated when a new layer is added to the scene.
Deleting a layer will not trigger an update because it's non-destructive.
Renaming a layer is equivalent to adding a new layer.
The working version of the scene composition is backed up if you set the
Backup Version option. Then, in Update mode, the working version is updated.
otherwise it is recreated from scratch (Recreate mode).
Existing render layer anchor link nodes are left unchanged because they point
to the latest version of the render layer composition by default. The ones that
are missing are created and linked to their respective render layer compositions.
If an existing render layer is no longer in the scene (because it was removed
from the 3D scene or because the pre-comp file update is partial), its anchor
link node is not deleted; the scene composition update is non-destructive—see
Non-Destructive Updates on page 314.
If the layer ordering or the blend modes between layers have changed, a new
stack of Blend & Comp nodes is created within a visual group next to the old
stack. In the following example, the tire and tire label layers were added during
update.
318 | Chapter 13 Pre-Compositing