presupposes a possibility to apply a set of outer forces and rigid or elastic constrains to grid structure nodes that allows the modelling of various outer effects. We may obtain the following expression for such SGM formulation where - total number of grid segments, - total number of nodes, - length of segment number , - stiffness of segment number , - coordinate increment of node at axis , - stiffness of an elastic constrain in node at axis , - outer force in node at axis . Unfolding problem and cutting pattern generation Once a satisfactory shape has been found, a cutting pattern may be generated. Tension structures are highly varied in their size, curvature and material stiffness. Cutting pattern approximation is strongly related to each of these factors. It is essential for a cutting pattern generation method to minimize possible approximation and to produce reliable plane cloth data. The objective is to develop the shapes described by these data, as close as possible to the ideal doubly curved strips. In general, cutting pattern generation involves two steps. First, the global surface of a tension structure is divided into individual cloths. The corresponding cutting pattern at the second step can be found by simply taking each cloth strip and unfolding it on a planar area. In the case of the ideal doubly curved membrane surface the subsurface cannot be simply unfolded and they must be flattened. For example, in, SGM has been used for the flattening problem solution. The cutting pattern generation problem is actually subdivided into two independent formulations. These are the generation of a distortion-free plane form unfolding each cloth strip and flattening double-curved surfaces that cannot be simply unfolded. Studying the problem carefully one can notice that from the position of differential geometry both formulations are the same. We may consider it as an isometric mapping of a surface onto the plane area that will be conformal mapping and equiareal mapping simultaneously because of invariant angles between any curves and invariance of any pieces of area. In the case of single-curved surface that can be unfolded precisely equi-areal mapping allows one to obtain a cutting pattern for fabric structure without any distortions. The second type of surfaces can be equi-areal mapped only approximately with some distortions of linear surface elements limited by the fabric properties. Let us assume that two surfaces are parameterized so that their