Customizing Nuke with Gizmos - Nuke 101: Professional Compositing and Visual Effects - page 515

functionalities, or trees that you know are taking care of a certain element of your comp,
inaGroup.Somecompositorsusethemmoreandsomeless.TocreateaGizmo,youhave
to first create a Group.
Like every other node, a Group node can hold User Knobs.
Everything in the DAG except for ColorBars1 is in charge of making the Safe Area
guides. So that's what you are going to place in the Group.
1. Select all nodes in the DAG except for Viewer1 and ColorBars1 and press Ctrl/
Cmd-G.
TheGroupOutputpanelthatpopsupwantstoknowwhichnodethatyouselected
will be the Group's output. Just as in any other node in Nuke, a Group node can
have many inputs, but only one output. In this case, there are only two nodes
for which the output is not in use: Merge2 and NoOp1. The output of the tree is
the output of Merge2—not NoOp1, which is unconnected to anything and is only
used as a holder of Knobs ( FIGURE 12.31 ) .
Figure 12.31. The Group Output panel.
2. In the Group Output panel that pops up, make sure that Merge2 is selected and
click OK ( FIGURE 12.32 ).
Figure 12.32. A Group is created instead of the tree.