Customizing Nuke with Gizmos - Nuke 101: Professional Compositing and Visual Effects - page 533

Using the Viewer Input Process
The Nuke Viewer can accept trees held in Groups and Gizmos into the Viewer Input Pro-
cess. These trees are then applied to the image before it is viewed in the Viewer (and only
in the Viewer). The Viewer Input Process will not be rendered on final output. This is de-
signed exactly for things like the Safe Area guides and other on-screen tools.
To load something into the Viewer Input Process, use the contextual menu.
1. Disconnect the pipe connecting Read1 and SafeAreas1.
2. View Read1 in the Viewer.
3. ClickSafeAreas1toselectit,thenright-click(Ctrl-click)todisplaythecontextual
menu. Choose Node then Use as Input Process from the menu ( FIGURE 12.52 ).
Figure 12.52. It's a long way to go, but the Use as Input Process option is
there in the end.