Particle Settings: Radius X & Y Seem Incorrectly Labelled

[mdgunn]

It seemed to me that for Particles Settings the Radius labels are not X and Y but something like 'Start Size' 'End Size', such as you may want to use for explosions, smoke etc where you want the emitted particle to grow or shrink over it's life time. If X and Y are correct then I suppose this means I don't understand what this is referring to and other new users may be equally confused.

 

In the image below Radius is set to used to shrink flames to form animated fire.