The Scale 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 which method is used to resize particles over their lifetime. There are four options:
Natural Scale: Specifies starting and ending scale percentages 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.
Rate: Specifies a steady rate at which particles change size over their entire lifetimes.
Birth and Death Values: Specifies starting and ending scale percentages 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 preexisting particle Scale (defined in the Cell Controls section of the Emitter Inspector).
Custom: Lets you customize the scale of the particles over their lifetime via a mini-curve editor (described below).
Scale At Birth: A slider (available when Increment Type is set to Natural Scale or Birth and Death Values) that defines the initial size of particles when they’re created. Click the disclosure triangle next to the Scale At Birth parameter to reveal separate X, Y, and Z subparameters. Use X and Y to change the width and height of generated particles; use Z to change the depth of 3D text particles.
Scale At Death: A slider (available when Increment Type is set to Natural Scale or Birth and Death Values) that defines the size of each particle at the end of its lifetime. Click the disclosure triangle next to the Scale At Death parameter to reveal separate X, Y, and Z subparameters. Use X and Y to change the width and height of generated particles; use Z to change the depth of 3D text particles.
Scale Rate: A slider (available when Increment Type is set to Rate) that defines how quickly each particle changes size. Positive values grow particles over time, while negative values shrink particles over time. Click the disclosure triangle next to the Scale Rate parameter to reveal separate X, Y, and Z subparameters. Use X and Y to change the width and height of generated particles; use Z to change the depth of 3D text particles.
Custom Scale controls: A group of controls (a mini-curve editor and two sliders, described below) appears when Increment Type is set to Custom. Use the mini-curve editor for more precise control over the Scale of particles in your particle system.
Mini-curve editor (unlabeled): A graph with the curves and control points you can drag to adjust the scale of particles in your particle system. For more information on using mini-curve editors, see Work in the mini-curve editor.
Custom Scale: A slider 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.