Hey Marco,
Interesting question. I had to check this a little bit. I might not have the best solution, but so far I think that is the fastest. After you have the result of the Hair you like, use the Generator Tab of the hair object and set it to Attribute Manager> Type>Spline. Then use the Object Manager>Object> Current State to Object function (while the Hair Object is active in the Object Manager.
You will be presented with a Spline-copy of the Hair. (You might disable the Hair Object now) .
In Point Mode you select all the Hair that you like to cut. Not where you like to cut, just the complete part that needs to go. While this selection is active, create a copy of it. Then use the Selection>Inverse command and delete the selected points. Click on the first copy of the Splines and delete its selection. You have now nearly a result of a “cut” of one object, but in two parts. Perhaps increase the selection from the cut part one time, as the cut with miss the spline between the selected points. This gives perhaps not a clean cut if the points on the spline are too far to each other. Do it one time, it might sounds not that abstract then. ;o)
The second Spline Object can now get a keyframe (pos/rot) and can be moved to a different position/orientation later in the scene, with a new keyframe.
Perhaps for a more natural effect, you could use the Pose Morph in Point-Mode or even a deformer object creates the motion that is needed.
If you render out the original Hair Object (dynamic> off!) and with a little overlap (time wise) you can cut the hair with an edit in Ae (traveling mask for example), then move it as said before.
You might tweak the material as the start and end point of the spline has changed now and so it would look like the part which was cut, starts the same “gradient” etc as the hair from the “head”. Thickness, color, etc., what ever you have set up, check it.
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Natively there is no direct way to have that effect of cut and split apart. Hair>Cut is a rout to cut only—not a cut to tip option.
There might be other options of course, the one above seems to be the one that gives the easiest way to manipulate the scene.
I have to check, but I think Patrick discussed growing Hair, but it has been a while since I visited this nice series.
All the best
Sassi
Image
https://www.amazon.com/clouddrive/share?s=5fN5QohzQzYhRd7E2P3gao
Sketch-scene
https://www.amazon.com/clouddrive/share?s=mS4mzO_iRQAu-4t9U7sP74
