First of all, you will to download the whole repository. Download the .zip
and unarchive it somewhere where you store your Nuke tricks (like ~/.nuke)
Add it to your Nuke's menu.py script using import, like so:
nuke.addPluginPath("/path/to/framecurve_nuke")
This will create a Framecurve menu in your Nodes toolbar, and add a couple of commands to the Animation context menu popup (this is the thing that appears when you right-click a knob).
Select a node in Nuke, and pick Load a framecurve from file and apply to selected node.
A dialog will pop out prompting you to select your framecurve file.
After the file is chosen the module will create a knob called framecurve in your node, and populate it with keyframes from the framecurve file.
If your framecurve file is in any way problematic, the import process will stop and show you all the issues encountered.
After the retiming curve has been imported, the script will walk all of your knobs in the node, and for each animated knob it will apply a timewarp expression which looks like this:
...and every animation in your node will become Framecurve-enabled and retimed.
You can also copy-paste the framecurve animation into another node as desired (for example into a F_Kronos timewarp)
If you only want to setup your node to handle the timewarp without loading any files, use Add retime to the selected node.
If you want to export a Framecurve file from an arbitrary knob, right-click on that knob and use the Framecurve menu. It's up to you to select a single-dimension knob of course (what would life on Earth be like if we had two-dimensional timewarps?)
These scripts use the framecurve_python library by Ben Dickson. That library is truly awesome and if you want to do anything sophisticated related to Framecurves we suggest you check it out.
The scripts here are covered with framecurve license.