public BoundingBox CalculateBoundingBox() { BoundingBox result = this.MinimumBoundingBox; if (LeftChild != null && !LeftChild.IsNilNode()) { result = result.Add(LeftChild.CalculateBoundingBox()); } if (RightChild != null && !RightChild.IsNilNode()) { result = result.Add(RightChild.CalculateBoundingBox()); } return(result); }