Viewer Lock

What is Viewer Lock?

Don't you hate it when your viewer's not connected to the nodes you think it's connected to? Like when you're rotoing and you're trying to A/B between the plate and the comp, but the roto node's overlay has hijacked Nuke's focus and now you're looking at some random roto node?

Usually when I ask people this, they say no. But I sure do, so I made this.

Viewer Lock is a tool that allows you to lock viewer inputs to nodes, so that they're always assigned to what you think they're assigned to. I've been using this personally for several years now and thought I'd share it in case there were people out there who also have this fairly niche problem.

Usage instructions

Press Shift+V to open the Viewer Lock panel, or, if you already have one open, to bring it to focus.

The left row of checkboxes show which inputs are in use. Uncheck them to unassign the input. The right row of checkboxes show which inputs are locked. Check them to lock the input to the node it's currently assigned to, or to uncheck them to unlock. The checkboxes at the top unassign all inputs and lock/unlock all inputs, respectively.

You can also use shortcuts:

• Ctrl+Alt+(number) will lock the input to the selected node, or reassign a locked input to the selected node.
• Ctrl+Shift+(number) will unlock the input and assign it to the selected node as normal.
• Ctrl+Alt+V and Ctrl+Shift+V will lock and unlock all inputs respectively.

This has not been tested with Nuke 14 or later.
This will not work with non-commercial Nuke because of Python restrictions. :(

Installation instructions

Unzip the downloaded VL.zip fille and move the menu.py and the viewerLock folder to your .nuke folder, keeping the contents of the viewerLock folder inside that folder. If you already have a menu.py file, combine it with this one.

Pipeline considerations?

Rather than a custom node, Viewer Lock is a Python script that is called by knobChanged callbacks and simply intercepts viewer hotkeys and reassigns viewer node inputs to make sure everything stays connected to where the user wants it to be. It works (almost*) entirely independently of the Nuke script and so using it has no impact on users who don't have it installed and may need to pick up your script.

*The only changes that Viewer Lock makes to a script is adding hidden checkbox knobs to viewer nodes to keep track of lock states between Nuke sessions. Without Viewer Lock they have no function and can't interfere with a script. You won't even know they're there. :)

What's new

Thank you to Szilárd Egyed for bringing my attention to a couple of things.

• Fixed a bug where closing Nuke would sometimes open up the crash window.
• Removed a updateUI callback, it provided little benefit and came with a performance cost.

Future support

I have been promising a major overhaul for years but one has never come, due to a few fairly boring factors which are unlikely to change any time soon (not least of which is the Foundry's overly restrictive Python limitations to the NC and Indie versions of Nuke). Rather than continuing to make a liar of myself, it's best to say that is most likely going to be the last update for ViewerLock for the foreseeable future.

However, Viewer Lock is simple enough and robust enough (despite the messy code) that I imagine it will continue to work for many years and many Nuke versions to come. Also, I make no claim to the source code, and anyone is free to download, improve, and redistribute Viewer Lock as they please.

I will continue to rely on this tool at work, so if there's ever a situation where it requires an update (e.g. any major changes to the Nuke Python API) you could expect me to upload that here.

Until then, all the best!

Copyright 2024 Matt Roe

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

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