ParticleSystem.MainModule.scalingMode

Description

Control how the Particle System applies its Transform component to the particles it emits.

Hierarchy: Scale according to its Transform and all its parents. Local: Scale using only its own Transform, ignoring all parents. Shape: Only apply scale to the source positions of the particles, but not their size. The source positions are defined by the Shape module.

using UnityEngine;
using System.Collections;

// add this to a Particle System which has a parent game object, to see how each scaling mode works
public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public float sliderValue = 1.0F;
    public float parentSliderValue = 1.0F;
    public ParticleSystemScalingMode scaleMode;

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

    void Update()
    {
        ps.transform.localScale = new Vector3(sliderValue, sliderValue, sliderValue);
        if (ps.transform.parent != null)
            ps.transform.parent.localScale = new Vector3(parentSliderValue, parentSliderValue, parentSliderValue);

        var main = ps.main;
        main.scalingMode = scaleMode;
    }

    void OnGUI()
    {
        scaleMode = (ParticleSystemScalingMode)GUI.SelectionGrid(new Rect(25, 25, 300, 30), (int)scaleMode, new GUIContent[] { new GUIContent("Hierarchy"), new GUIContent("Local"), new GUIContent("Shape") }, 3);
        GUI.Label(new Rect(25, 80, 100, 30), "Scale");
        sliderValue = GUI.HorizontalSlider(new Rect(125, 85, 100, 30), sliderValue, 0.0F, 5.0F);
        GUI.Label(new Rect(25, 120, 100, 30), "Parent Scale");
        parentSliderValue = GUI.HorizontalSlider(new Rect(125, 125, 100, 30), parentSliderValue, 0.0F, 5.0F);
    }
}