# ParticleSystem.LifetimeByEmitterSpeedModule

> The Lifetime By Emitter Speed Module controls the initial lifetime of each particle based on the speed of the emitter when the particle was spawned.

## Definition

* **Type:** Struct
* **Namespace:** [UnityEngine](/engine/6000.3/script-reference/unityengine.md)
* **Assembly:** UnityEngine.ParticleSystemModule

```csharp
public struct ParticleSystem.LifetimeByEmitterSpeedModule
```

## Remarks

This module multiplies the start lifetime of particles with a value that depends on the speed of the object that spawned them. For most Particle Systems, this is the GameObject velocity, but for sub-emitters, the velocity comes from the parent particle that the sub-emitter particle originated from.

Additional Resources: [ParticleSystem](/engine/6000.3/script-reference/unityengine/particlesystem.md), [ParticleSystem.MainModule.startLifetime](/engine/6000.3/script-reference/unityengine/particlesystem/mainmodule/startlifetime.md).

## Properties

| Property                                                                                                                      | Description                                                                                                                                             |
| ----------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [curve](/engine/6000.3/script-reference/unityengine/particlesystem/lifetimebyemitterspeedmodule/curve.md)                     | Use this curve to define which value to multiply the start lifetime of a particle with, based on the speed of the emitter when the particle is spawned. |
| [curveMultiplier](/engine/6000.3/script-reference/unityengine/particlesystem/lifetimebyemitterspeedmodule/curvemultiplier.md) | Use this property to change the curve multiplier.                                                                                                       |
| [enabled](/engine/6000.3/script-reference/unityengine/particlesystem/lifetimebyemitterspeedmodule/enabled.md)                 | Use this property to enable or disable the LifetimeByEmitterSpeed module.                                                                               |
| [range](/engine/6000.3/script-reference/unityengine/particlesystem/lifetimebyemitterspeedmodule/range.md)                     | Control the start lifetime multiplier between these minimum and maximum speeds of the emitter.                                                          |