Size over Lifetime module

Many effects involve a particle changing size according to a curve, which can be set in this module.

Using the Size over Lifetime module

This module is part of the Particle SystemA component that simulates fluid entities such as liquids, clouds and flames by generating and animating large numbers of small 2D images in the scene. More info
See in Glossary component. When you create a new Particle System GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary, or add a Particle System component to an exiting GameObject, Unity adds the Size over Lifetime module to the Particle System. By default, Unity disables this module. To create a new Particle System and enable this module:

1. Click GameObject > Effects > Particle System.
2. In the InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
   See in Glossary, find the Particle System component.
3. In the Particle System component, find the Size over Lifetime module fold-out.
4. To the left of the fold-out header, enable the checkbox.

API

Since this module is part of the Particle System component, you access it through the ParticleSystem class. For information on how to access it and change values at runtime, see the Size over Lifetime module API documentation.

Properties

For some properties in this section, you can use different modes to set their value. For information on the modes you can use, see Varying properties over time.

Details

Some particles will typically change in size as they move away from the point of emission, such as those that represent gases, flames or smoke. For example, smoke will tend to disperse and occupy a larger volume over time. You can achieve this by setting the curve for the smoke particle to an upward ramp, increasing with the particle’s age. You can also further enhance this effect using the Color Over Lifetime module to fade the smoke as it spreads.

For fireballs created by burning fuel, the flame particles will tend to expand after emission but then fade and shrink as the fuel is used up and the flame dissipates. In this case, the curve would have a rising “hump” that rises and then falls back down to a smaller size.

The values specified in the curves are multiplied by the Start Size to get the final particle size.

Non-uniform particle scaling

You can specify how a particle’s width, height and depth changes over lifetime independently. In the Size over Lifetime module, check the Separate Axes checkbox, then change the X (width), Y (height) and Z (depth). Remember that Z will only be used for MeshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
See in Glossary particles.