Size Curve Behavior
This behavior changes a particle's size over the course of its lifetime.
SizeCurve: A curve which is used to look up the size of the particle. The current fraction of the particle's lifespan is used for the lookup along the X axis. The absolute X and Y values in the curve don't matter, the curve is normalized to [0; 1] range.
BaseSize: The particles will always have at least this size, the rest is added on top.
CurveScale: Specifies what value the largest value in the curve maps to. That means at the peak of a curve, the particle's size will be BaseSize + CurveScale.