A duration of 0.0 specifies that all particles (the value of the birthRate property) spawn instantaneously. Use this duration to create randomized static effects in your scene. For example, by combining this option with the birthLocation and imageSequenceInitialFrameVariation properties, you can cover a plane with a variety of sprites, creating the appearance of a grassy field.
The range of randomized particle birth rate values. Animatable.
This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.