Here is a super easy way to make a surface that is curved in 2 directions.
The Boundary Surface command makes you think that it needs 2 curves in each direction,
but all that is really required is one each way !
Piece of cake !!
If you want to learn other awesome SURFACING tips & tricks, you should attend 3DVision Technologies Advanced Surfacing class. See the website for details. Or contac us at (513) 745-2700