This is a very flexible and adaptive filter to inject and track particles in a flow. It takes three inputs :
 * port 0 : Flow Input, a volumic dataset containing data to integrate with, any kind of data object, support distributed input.
 * port 1 : Seed (source) Input, a dataset containing point to generate particles with, any kind of data object, support distributed input. Only first leaf of composite dataset is used.
 * port 2 : Optional Surface Input, containing dataset to interact with, any kind of data object, support distributed input.

It has two outputs :
 * port 0 : ParticlePaths : a polyData of polyLines showing the paths of particles in the flow
 * port 1 : ParticleInteractions : empty if no surface input, contains a polydata of vertex
   with the same composite layout of surface input if any, showing all interactions between particles and the surface input

It has a parallel implementation wich streams particle between domains.

The most important parameter...