Unity 3D FadeTest - Fade object alpha over time.

FadeTest.cs

using UnityEngine;
using System.Collections;

public class FadeTest : MonoBehaviour
{
    Color startColor;
    Color currentColor;
    Color endColor;
    bool shouldFade = false;
    float startTime;
    float endTime;
    public float seconds = 5.0f;
    float t;

    // Use this for initialization
    void Start ()
    {
      Debug.Log ("FadeTest used by " + gameObject.name);
      startColor = gameObject.renderer.material.color;
      endColor = new Color(startColor.r, startColor.g, startColor.b, 0.0f);
      int childCount = transform.childCount;
      for ( int childIndex = 0; childIndex < childCount; childIndex++)
      {
        Transform child = gameObject.transform.GetChild(childIndex);
        if (child.gameObject.renderer) {
          child.gameObject.AddComponent<FadeTest>();
        }
      }
    }

    // Update is called once per frame
    void Update ()
    {
      if(Input.GetKeyUp(KeyCode.F))
      {
        shouldFade = true;
        startTime = Time.time;
        endTime = startTime + seconds;
      }

      Fade();
    }
    void Fade()
    {
      if ( shouldFade )
      {
        t = Time.time / endTime;
        currentColor = Color.Lerp(startColor, endColor, t);
        gameObject.renderer.material.SetColor("_Color", currentColor);

        if ( currentColor == endColor )
        {
          shouldFade = false;
          startTime = 0.0f;
          endTime = 0.0f;
          t= 0.0f;
        }
      }
    }
}