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Auto Domain [ADoD]
The Auto Domain node
Auto Domain Node Introduction
The Auto Domain node automatically sets the image’s domain of definition (DoD) based on
bounds of the input image’s background Canvas color. It does not change the image’s physical
dimensions. Some EXR images come with optimized DoDs already set, but other formats do
not. For formats other than EXR, this node can speed up compositions by optimizing the DoD
based on the content rather than the frame’s dimensions.
For example, a CG character rarely takes up the entire frame of an image. With this type of
image, the Auto Domain node sets the DoD to a rectangular region by comparing image pixels
with the Canvas color. The Canvas color indicates what color the pixels are outside the DoD.
Bydefault, unless a Canvas color is set using the Set Canvas Color node, the color is set to
black. This default works well when an image has a premultiplied Alpha channel. The result is a
DoD that encompasses the portion of the clip that contains only the character. The DoD is
updated on each frame to accommodate changes, such as a character walking closer to the
camera. However, if a clip does not contain an Alpha channel, the Set Canvas Color node can be
used to define the Canvas color as solid Alpha with a color that matches the solid background.
See Chapter 34, “Color Nodes” in the Fusion Studio manual or Chapter 85 in the
DaVinci Resolve manual for more detail on the Set Canvas Color node.
NOTE: The Domain of Definition is a bounding box that encompasses pixels that have
a nonzero value. The DoD is used to limit image-processing calculations and speeds
up rendering.
Inputs
The single input on the Auto Domain node is used to connect a 2D image and an effect mask,
which can be used to limit the blurred area.
Input: The orange input is used for the primary 2D image that is blurred.
Effect Mask: The blue input is for a mask shape created by polylines, basic primitive
shapes, paint strokes, or bitmaps from other tools. Connecting a mask to this input
limits the blur to only those pixels within the mask.
Basic Node Setup
The example below assumes that the image does not contain an Alpha channel but a CG
character rendered against a black background. This is common for different render passes like
specular or shadows, for example. The image is connected to a Set Canvas Color node, which
sets the Canvas color to black with a solid Alpha. The Set Canvas Color then connects to the
Auto Domain node, which detects the pixels and sets the DoD. If the original image contained a
premultiplied Alpha channel, the Set Canvas Color would not be needed, and the image could
be connected directly into the Auto Domain node.
Chapter – 100 Miscellaneous Nodes 2205