Is there anyway to reset/clear Trail Renderer?

New Unity version has a Clear method for trails: http://docs.unity3d.com/ScriptReference/TrailRenderer.Clear.html

If this option is not available for you I recommend resetting the time in the OnRenderObject callback of your script:

     void OnRenderObject()
     {
         if (!float.IsNaN(_ClearTimeS))
         {
             _TrailRenderer.time = _ClearTimeS;
             _ClearTimeS = float.NaN;
         }
     }

     private float _ClearTimeS = float.NaN;

     public void Clear()
     {
         if (!float.IsNaN(_ClearTimeS)) return;
         _ClearTimeS = _TrailRenderer.time;
         _TrailRenderer.time = 0;
     }

GetComponent<TrailRenderer>().Clear()

handles this as of 5.3

https://docs.unity3d.com/530/Documentation/ScriptReference/TrailRenderer.Clear.html

The following works for me to move a trailed object without it streaking.

Place this extension in a c# file somewhere in your assets folder.

 public static class TrainRendererExtensions
 {
     /// <summary>
     /// Reset the trail so it can be moved without streaking
     /// </summary>
     public static void Reset(this TrailRenderer trail, MonoBehaviour instance)
     {
         instance.StartCoroutine(ResetTrail(trail));   
     }
 
     /// <summary>
     /// Coroutine to reset a trail renderer trail
     /// </summary>
     /// <param name="trail"></param>
     /// <returns></returns>
     static IEnumerator ResetTrail(TrailRenderer trail)
     {
         var trailTime = trail.time;
         trail.time = 0;
         yield return 0;
         trail.time = trailTime;
     }        
 }

then use it from within a monobehavior like so

 trail.Reset(this);

see also

• http://answers.unity3d.com/questions/50009/recycled-trailers-leave-streaks.html

• http://forum.unity3d.com/threads/trailrenderer-reset.38927/