Compositing CGI with Bigger Node Trees - Nuke 101: Professional Compositing and Visual Effects - page 95

Viewing channel sets with the Viewer
The 3D render displayed in the Viewer, which you brought in from the disk, is an EXR
file that holds the beauty pass (a combination of all the other passes, if you will) in the
RGBA channel set along with all the channel sets that make up the image. To view these
other channels, use the Viewer's Channel buttons ( FIGURE 3.2 ).
Figure 3.2. Use these three Channel buttons to display different channels in the
Viewer.
The three buttons at the top left of the Viewer are the Channel buttons. The button on the
left shows the selected channel set; by default the RGBA set is chosen. The button in the
middle shows which channel to display when viewing the alpha channel; by default it is
rgba.alpha. The button on the right shows which channel from the set you have currently
chosen is being viewed; by default, it is RGB.
If you want to view the second channel of a channel set called Reflection Pass, for ex-
ample, you need to change the leftmost button to show the Reflection Pass channel set,
and then set the third button to green channel (G is the second letter in RGBA—hence,
second channel).
1. ClicktheChannelSetViewerbutton(theoneontheleft)andviewallthechannel
sets you can now choose from ( FIGURE 3.3 ) .
Figure 3.3. The list of all the channel sets available in the stream being
viewed.