You are using 3D noise for grid line ? Maybe 2D noise, The third cord is the noise it’s self in 2D, so you plan X,Y outside the perlin noise factor to draw a grid line first then you fill it with noise, since the grid line is defined first maybe this way you can pull off what you want. You plot X,Y then draw Z there (noise).
On a grid line you plot X-Y, (where to plot), then Z to draw the noise at the X-Y you chose, so Z is the noise Variable and X,Y is perhaps your looping system. In this case the Z has all the noise (x,y) in it from perlin noise lib.
So think of it this way, you have an x and a y on the grid system where you create the grid line, then you got the Z where you plot noise on the X-y you build, but this Z (the noise) contains it’s own x,Y to draw noise at the other x-y you created (the grid line) So you have an X-Y and then this determins where you are going to plot your X,Y from the noise. So it’s an X-Y (your noise) representing Z inside the X-Y(your grid line). An X,Y inside an X-Y how about that.
You would have to figure out how to extend it infinite I guess, so it draws a radius then stops then you move it draws more and so on.
Also your noise function is a bit funny, it’s missing the Z cord, it’s " FMath::PerlinNoise3D" but you only have X,Y there for data variable, I take it zero is the Z but it has undefined value.
You only use 3d noise when you are building 3d objects, like cubes, shapes that are objects.