void UpdatePreview(float time)
 {
     if (previewTarget != null)
     {
         if (previewTarget.blendSystem != null)
         {
             if (previewTarget.blendSystem.isReady)
             {
                 previewTarget.PreviewAtTime(time);
                 EditorUtility.SetDirty(previewTarget.blendSystem);
             }
         }
     }
 }