/// <summary>
 /// Gets tangent for a given relative position
 /// </summary>
 /// <param name="tf">relative position</param>
 /// <returns></returns>
 protected override Vector3 GetTangent(float tf)
 {
     return((Space == Space.World) ? Path.Module.Generator.transform.TransformDirection(PathData.InterpolateDirection(tf)) : PathData.InterpolateDirection(tf));
 }