/// <summary>
 /// Returns the bounding box containing this box and the given box.
 /// </summary>
 public Box3d Enlarge(Box3d r)
 {
     return(new Box3d(Math.Min(Min.x, r.Min.x), Math.Max(Max.x, r.Max.x),
                      Math.Min(Min.y, r.Min.y), Math.Max(Max.y, r.Max.y),
                      Math.Min(Min.z, r.Min.z), Math.Max(Max.z, r.Max.z)));
 }
 public Box3d(Box3d box)
 {
     Min = box.Min;
     Max = box.Max;
 }
 public FRUSTUM_VISIBILTY GetVisibility(Box3d box)
 {
     return(GetVisibility(Planes, box));
 }