User Manual

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XYZ (CIE Format): This mode is used to convert a CIE XYZ image to and from RGB
color spaces. CIE XYZ is a weighted space, instead of a nonlinear one, unlike the other
available color spaces. Nonlinear in this context means that equal changes in value at
different positions in the color space may not necessarily produce the same magnitude
of change visually to the eye.
Expressed simply, the CIE color space is a perceptual color system, with weighted
values obtained from experiments where subjects were asked to match an existing
light source using three primary light sources.
This color space is most often used to perform gamut conversion and color space
matching between image display formats because it contains the entire gamut of
perceivable colors.
Negative: The color channels are inverted. The color space remains RGBA.
BW: The image is converted to black and white. The contribution of each channel
to the luminance of the image is adjustable via slider controls that appear when this
option is selected. The default values of these sliders represent the usual perceptual
contribution of each channel to an image’s luminance. The color space of the image
remains RGBA.
Settings Tab
The Settings tab in the Inspector is also duplicated in other Color nodes. These common
controls are described in detail at the end of this chapter in “The Common Controls” section.
Copy Aux [CPA]
The CopyAux node
Copy Aux Node Introduction
The Copy Aux node is used to shuffle channels between visible channels and auxiliary data
channels in a single 2D image. Typically, these auxiliary channels are rendered from 3D
applications. Auxiliary channels supported in the Copy Aux node include background color,
z-depth, texture coordinates, coverage, object ID, material ID, normals, vectors, back vectors,
and world position.
The Copy Aux node is mostly a convenience node, as the copying can also be accomplished
with more effort using a Channel Booleans node. Where Channel Booleans deals with
individual channels, Copy Aux deals with channel groups. By default, the Copy Aux node
automatically promotes the depth of its output to match the depth of the aux channel.
Copy Aux also supports static normalization ranges. The advantage of static normalization
versus the dynamic normalization that Fusion’s viewers do is that colors remain constant over
time. For example, if you are viewing Z or WorldPos values for a ball, you see a smooth gradient
from white to black. Now imagine that some other 3D object is introduced into the background
at a certain time. Dynamic normalization turns the ball almost completely white while the
background object is now the new black. Dynamic normalization also causes flicker problems
while viewing vector/disparity channels, which can make it difficult to compare the aux channels
of two frames at different times visually.
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