Apple Motion 3 User Manual
Page 739
Chapter 8
Working with Particles
739
Scale Over Life
This behavior lets you grow or shrink 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.
Increment Type: Choose an option from this pop-up menu to determine which
method is used to resize particles over their lifetime. There are four options:
 Natural Scale: Specifies starting and ending scale percentages that are used to
animate each particle’s size over its lifetime. Natural Scale uses an exponential curve
to allow the animation to progress slowly when the scale values are small, and speed
up when the values are large. This creates the illusion that the scaling is occurring at
a constant speed. When Natural Scale is selected, the Scale At Birth and Scale At
Death parameters become available.
 Scale At Birth: Determines the initial size of particles when they are created.
 Scale At Death: Determines the size of each particle at the end of its lifetime.
 Rate: Specifies a steady rate at which particles change size over their entire lifetimes.
When Rate is selected, the Scale Rate parameter becomes available.
 Scale Rate: Allows you to define how quickly each particle changes size. Positive
values grow particles over time, while negative values shrink particles over time.
 Birth and Death Values: Specifies starting and ending scale percentages that are
used to animate each particle’s size over its lifetime. The scale amount generated by
this option for a specific particle at a specific time is multiplied by the pre-existing
particle Scale (defined in the Cell Controls section of the Emitter tab). When this
option is selected, the Scale At Birth and Scale At Death parameters become
available.
 Scale At Birth: Determines the initial size of the particles when they are created.
 Scale At Death: Determines the size of the particles at the end of their lifetime.
 Custom: This mini-curve editor allows you to customize the scale 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 “
 Custom Scale: Use this slider to adjust the value of the selected keyframe in the
mini-curve editor.
 Over Life: Use this slider to adjust the position of the selected keyframe in the life
of the particle.
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: