A single-analysis, simple, non-iterative method of structural optimization is proposed for sheet-stringer problems. It can accommodate a variety of objective functions such as critical stress, minimum weight, specified frequency, desired displacement, dynamic stress, etc. for static, eigen, transient and steady state dynamic response problems. The design variables can be continuous or discrete. This method had been extended to in-plane membrane-truss systems. With proper selection of stiffener sections it can even be applied to curved stiffened shells. Applications to composite structures and to a class of non-linear systems are also stated. The time-consuming classical iterative methods are avoided by this non-iterative scheme. This method uses the lattice analogy of Hrennikoff and the principles of scaling. The mathematical bases for the static, dynamic and response problems are given. Example problems also show the utility of this method in structures with cutouts. The limitations of this work are also stated.