A new tool that will make a particle flowing along the maximum gradient on a mesh. If no weights on mesh vertex, the tool will use the height of the vertex, so by default it is a Rain Flow. A step is per face so you don’t need to input a step distance but rather a maximum number of steps.

Lets say I put a weight of 100 of the red dot and 0 at all others places. And then I smooth the weights. I could also use geodesic distance or heat flow.

The idea is to populate each vertex of the mesh with an angle and to limit the maximum angle. As the tool follow the gradient going from high value to lower, the angle with Z is negated.

On version 1.4 I added some tool that are a bit more generic.
In order to generate a flow the tool must have a Vector for each vertex of the mesh.
Vectors could be generated by

Version 1.5 brings some improvements and bug removal.
Now mesh vertices works well. Tell me if there is a problem.
There is now a component with a better field evaluation
From this