# shadowBias

> Apply a shadow bias to prevent self-shadowing artifacts. The specified value is the proportion of the trail width at each segment.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.5/script-reference/unityengine.md)
* **Assembly:** UnityEngine.ParticleSystemModule

```csharp
public float shadowBias { get; set; }
```

### Examples

```csharp
using UnityEngine;
using System.Collections;

[RequireComponent(typeof(ParticleSystem))]
public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public float hSliderValueBias = 1.0f;

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

        var main = ps.main;
        main.startColor = new ParticleSystem.MinMaxGradient(Color.red, Color.yellow);
        main.startSize = 0.1f;

        var trails = ps.trails;
        trails.enabled = true;

        var psr = GetComponent<ParticleSystemRenderer>();
        psr.trailMaterial = new Material(Shader.Find("Sprites/Default"));
    }

    void Update()
    {
        var trails = ps.trails;
        trails.shadowBias = hSliderValueBias;
    }

    void OnGUI()
    {
        GUI.Label(new Rect(25, 40, 100, 30), "Shadow Bias");

        hSliderValueBias = GUI.HorizontalSlider(new Rect(55, 45, 100, 30), hSliderValueBias, 0.0f, 1.0f);
    }
}
```