Changes the current particle emitter scale rate.
#ParticleEmitter The particle emitter to use. Rate The new particle emitter scale rate. The default rate is 0, which means the particle will be the same size. When using a value greater than 0, the particle size will be increase over time (each second, the rate will be added to the current size). When using a value lower than 0, the particle size will be decreased over time (each second, the rate will be substracted from the current size).
A rate of 10 will increase the particle size of 10 units per second.
A rate of -2 will decrease the particle size of 2 units per second.