The Spin Over Life behavior has one main parameter control and three optional parameter controls that vary, depending on the selected Increment Type:
Increment Type: A pop-up menu that sets the method used to spin particles over their lifetimes. There are three options:
Rate: Specifies a steady rate and direction in which particles spin over their lifetime.
Birth and Death Values: Specifies starting and ending spin degrees used to animate each particle’s rotation over its lifetime. The spin amount generated by this option for a specific particle at a specific time is added to the preexisting particle spin (defined in the Cell Controls section of the Emitter Inspector).
Custom: Lets you customize the spin of the particles over their lifetimes with a mini-curve editor (described below).
Spin Rate: A slider (available when Increment Type is set to Rate) that determines how quickly each particle spins and the direction of the spin. Positive values spin particles faster over time and in a counterclockwise direction; negative values spin particles slower over time and in a clockwise direction.
Spin At Birth: A slider (available when Increment Type is set to Birth and Death Values) that determines the initial spin of the particles when they’re created.
Spin At Death: A slider (available when Increment Type is set to Birth and Death Values) that determines the spin of the particles at the end of their lifetimes.
Custom Spin controls: A group of controls (a mini-curve editor and several other controls, described below) available when Increment Type is set to Custom. Use the mini-curve editor for more precise control over the Spin of particles in your particle system.
Mini-curve editor (unlabeled): A graph with curves and control points you can drag to adjust the spin of particles. For more information on using mini-curve editors, see Work in the mini-curve editor.
Custom Spin: A dial to adjust the value of the selected keyframe in the mini-curve editor.
Over Life: A slider to adjust the position of the selected keyframe in the life of the particle.