This tool uses the POP Drag node to define a drag to particles. When a force is applied to particles, it makes them move faster and faster. Drag helps slow down the particles so that they do not infinitely increase their speed. Drag can also be used to simulate things moving through water or other high density spaces.

1. Create a particle system along the curve using the Location or Source shelf tools.

2. Click the Drag tool on the Particles tab.