ParticleSystem.ShapeModule.enabled

Description

Specifies whether the ShapeModule is enabled or disabled.

Additional resources: ParticleSystem.shape.

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(ParticleSystem))]
public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public bool moduleEnabled = true;

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

    void Update()
    {
        var shape = ps.shape;
        shape.enabled = moduleEnabled;
    }

    void OnGUI()
    {
        moduleEnabled = GUI.Toggle(new Rect(25, 25, 200, 30), moduleEnabled, "Enabled");
    }
}