Can Blender's Freestyle outline have a line boil that happens on 3's?

Question

I'm trying to figure out a way to adjust frame rate of the freestyle line boil in Blender. Currently, I can only seem to have it boil on 1's. Meaning every frame of footage, the outline moves a bit. I would like to figure out if its possible to have the freestyle line boil happen on 3's. Meaning the line boils on one frame, stays unmoved for 2 frames, and then boils to a new position on the 3rd frame, then 6th frame, then 9th frame, etc.

Is it possible to have a scene playing at 24 fps and have a freestyle element that is moving and animating its lines at a slower frame rate? Like if a camera was moving on 1's and the scene is 24fps, but a passing object with freestyle linework was on 3's. Is that possible? I'm looking for a way to get that choppier line effect but still have the scene as a whole play out at 24fps.

This is the type of line I'm looking to emulate, and its helped me so far! Thanks so much for any input. Does anyone know how to make my 3d model's outline look like a boiling line animation effect? like Ed, Edd n Eddy

Answer 1

The answer is already in the other answer you have linked to - you just have to modify it a little bit.

In the linked answer, the frame change is used as driver to change the noise seed. There the fmod function is used to create a loop of alternating seeds. The only question that remains is, do you want a loop or just a continuous change? Here are solutions for both:

Since you want to change it on every third frame instead of each frame, the secret is simply to divide the frame number by 3.

1. For a looping seed, enter #fmod(frame/3,x) into the Seed value field. The # at the beginning creates a driver (it disappears afterwards when you edit the entry), the x you have to replace with a number of how many different seeds you want to be looping.
2. For a constantly changing seed, simply enter #frame/3 into the Seed value field.

The Seed value has to be an integer number, so technically you could write floor(frame/3) wherever you have frame/3, but since that field only accepts integers, the resulting values will automatically be floored to the next lower integer.

In the original answer Markus adds 500 to the result to avoid a bug whenever the formula results in 0, however this bug does not seem to be there anymore (version 4.1). But nevertheless you can add something (at the front or the end, does not matter) to change the base of the seed.

Here the resulting seeds of the two formulas (with x = 2 for the first), each of them changes the seed every third frame, either alternatingly or progressively: