ParticleSystem.LifetimeByEmitterSpeedModule.range

Description

Control the start lifetime multiplier between these minimum and maximum speeds of the emitter.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public bool moduleEnabled = true;
    public float maxSpeed = 5.0f;
    public AnimationCurve curve = AnimationCurve.EaseInOut(0.0f, 1.0f, 1.0f, 0.2f);

    void Start()
    {
        ps = GetComponent<ParticleSystem>();

        var mainModule = ps.main;
        mainModule.startLifetime = 1.0f;

        // make particles less random to more clearly see effect of lifetime.
        var shapeModule = ps.shape;
        shapeModule.radius = 0.1f;
        shapeModule.angle = 1.0f;

        var main = ps.main;
        main.simulationSpace = ParticleSystemSimulationSpace.World;

        // add a sphere so we can see our transform position as it moves
        var sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
        sphere.transform.parent = ps.transform;
    }

    void Update()
    {
        var lifetimeByEmitterSpeed = ps.lifetimeByEmitterSpeed;
        lifetimeByEmitterSpeed.enabled = moduleEnabled;
        lifetimeByEmitterSpeed.range = new Vector2(0, maxSpeed);
        lifetimeByEmitterSpeed.curve = new ParticleSystem.MinMaxCurve(1f, curve);

        ps.transform.position = new Vector3(Mathf.Sin(Time.time * 2.0f) * 4.0f, 0.0f, 0.0f);
    }

    void OnGUI()
    {
        moduleEnabled = GUI.Toggle(new Rect(25, 45, 100, 30), moduleEnabled, "Enabled");
        maxSpeed = GUI.HorizontalSlider(new Rect(25, 85, 100, 30), maxSpeed, 0.0f, 10.0f);
    }
}