Spin Over Life
This behavior lets you spin the particles in a system over the duration of each particle’s
life. It has one main parameter and three optional parameters that appear depending on
the selected Increment Type.
Parameters in the Inspector
Increment Type:
A pop-up menu that determines which method is used to spin particles
over their lifetime. There are three options:
• Rate: Specifies a steady rate and direction in which particles spin over their lifetime.
When Rate is selected, the Spin Rate parameter becomes available.
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Chapter 14
Working with Particles
• 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 pre-existing particle spin (defined
in the Cell Controls section of the Emitter Inspector). When this option is selected, the
Spin At Birth and Spin At Death parameters become available.
• Custom: When Increment Type is set to Custom, a mini-curve editor appears that allows
you to customize the spin of the particles over their lifetime. Click the disclosure triangle
to display the mini-curve editor in the Inspector. For more information on using
mini-curve editors, see
Mini-Curve Editor
.
Spin Rate:
Allows you to define 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:
Determines the initial spin of the particles when they are created.
Spin At Death:
Determines the spin of the particles at the end of their lifetime.
Custom Spin:
This group of parameters appears when Increment Type is set to Custom.
Use this mini-curve editor for more precise control over the Spin of particles in your
particle system.
• Custom Spin: Use this control to adjust the value of the selected keyframe in the
mini-curve editor. This parameter appears when Custom is selected in the Increment
Type pop-up menu.
• Over Life: Use this slider to adjust the position of the selected keyframe in the life of
the particle. This parameter appears when Custom is selected in the Increment Type
pop-up menu.
HUD Controls
The HUD contains the Increment Type pop-up menu, and the Spin Rate, Spin At Birth,
and Spin At Death parameters.