Empty Flow provides a starting point for a particle system consisting of a single global event containing a Render operator. This lets you build a system completely from scratch, without having first to delete the default operators provided by the Standard Flow system.
To use Empty Flow, drag it from the depot to the event display. In Particle View, this creates a global event containing a
single Render operator. If the Global default display option is active in the Particle View 
Options menu, the global event will also contain a Display operator. Adding an Empty Flow also creates a Particle Flow Source
icon in the viewports, at the world origin (0,0,0).
