Noise direction node

This modifier can be used to add noisiness to the direction pathlines.

Scale

Sets the size of the noise effect (not strength). Larger values produce smoother noise, lower values more jagged noise.

Phase

Shifts the start and end points of the underlying wave.

Random seed

When on, all path lines will be built differently.

Strength parameters group

Allows the user to set up the value of noise amplitude.

Strength

Controls the magnitude of the noise effect.

X, Y

Sets the strength scale of the noise effect along each of two axes.

Fractal parameters group

Allows the user to configure the parameters of fractal noise.

Roughness

Determines the extent of fractal variation. Lower values are less rough than higher values. Range=0.0 to 1.0. Default=0.0.

Iterations

Controls the number of iterations (or octaves) used by the fractal function. Fewer iterations use less fractal energy and generate a smoother effect. An iteration of 1.0 is the same as turning Fractal off. Range=1.0 to 10.0. Default=3.0.

Shift Start Point

When off, shifts a path line so that the starting point coincides with the distribution point. In previous versions the noise modifier shifts all path's points relative to the axis. Now, using this option, the starting points keeps its original positions. Mainly for compatibility with previous versions. Default=off, but if you open a file saved in the old version, this option is on.

The right connectors allows to connect the Curve node to control the values of the corresponding parameters along the pathlines.

An example: