It makes the path lines react to other path lines, in other words, it makes them reflect and/or attracted to the lines.
For example, this allows to protect some branches from penetration into other branches.
Allows to adjust the reflection path lines from the other lines.
Turns the reflection function on.
Specifies the distance to other path lines, when it's reached, the direction of the path line will change.
Allows to adjust the attraction path liness to other lines.
Turns the magnetic function on.
Specifies the distance between the path lines, when it's reached, the path lines begin to attract.
Percentage value, showing how strongly the magnetic points capture the path lines.
Sets the principle of generation of the magnetic points.
The points of the path lines are used as magnetic points.
An additional magnetic points will be generated on the path lines.
Sets the distance between an additional magnetic points on the segment. Decreasing the value will increase density of points on the segment. The magnetic points are generated randomly, so the distance may be not accurate.
When on, displays magnetic points on paths in the Viewport.
The right connectors allows to connect the Curve node to control the values of the corresponding parameters along the pathlines.
Possible result without Path reaction modifier:
Result when using the Path reaction modifier: