In this work, a resource-saving technique is proposed for shape optimization of thin-wall constructions by using metamodels in the form of local polynomial approximations. The technique is based on using the commercial CAD software as well as the original code EDAOpt developed in RTU for the design of experiments, approximation and optimization. The technique considers designing of the location of the control points of the polygon of non-uniform rational B-splines for shape definition and building of the appropriate metamodels of the responses for subsequent implementation of optimization. The technique is discussed on the base of solution of two test problems. The first one is concerned with shape optimization of the plate bending problem with displacement constraints, and the second problem is concerned with shape optimization of the plate biaxial tension problem with stress constraints. The efficiency of three procedures of the shape definition is analyzed. As shown above, utilization of the proposed technique and definition of shape by the procedure of the polygon control points of non-uniform rational B-splines give better results than those obtained by the classical homogenization method. The smooth shapes defined by B-splines are obtained using the proposed technique. The jagged shapes are not analyzed and are excluded from the optimization process. The obtained shapes are implemented in a technologically easy way; at the same time, their design does not require large computational resources. Consequently, optimization can be carried out on an ordinary personal computer