Version: 2018.2
public float flipRotation ;

Description

Makes some particles spin in the opposite direction.

Set between 0 and 1, where higher values will cause a higher proportion of particles to spin in the opposite direction.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { private ParticleSystem ps; public float hSliderValue = 0.0F;

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

var rot = ps.rotationOverLifetime; rot.enabled = true; rot.zMultiplier = 90.0f * Mathf.Deg2Rad;

var psr = GetComponent<ParticleSystemRenderer>(); psr.material = new Material(Shader.Find("Sprites/Default")); // this material renders a square billboard, so we can see the rotation }

void Update() { var main = ps.main; main.flipRotation = hSliderValue; }

void OnGUI() { hSliderValue = GUI.HorizontalSlider(new Rect(25, 25, 100, 30), hSliderValue, 0.0F, 1.0F); } }