The particles in the system come and go on their own. In fact, we can alter the ways that particles travel across the window. In this section, we introduce different ways to apply forces to the particles so that they can travel in different manners. The first object is part_damp. It is a damping force that changes the speed of each particle.
Have a look at the Particle003.pd patch in the following screenshot:
The part_damp object takes three numbers representing X, Y, and Z directions of the force. Values larger than 1 speed up the particles, while values smaller than 1 slow them down. It is pretty straightforward. The second object is part_gravity. It simulates the attraction of gravity. The next patch Particle004.pd demonstrates its usage as shown in the following screenshot:
The object part_gravity also comes with three numeric parameters in its right inlet. To simulate the gravity, we usually only specify the Y direction with a small negative number...