We present an integrated set of programs as CAD-tools for the design of shapes, evaluation of stress field and displacements of tensile membrane structures as well as a way to find out their surface patterns. In early times simulation of physical small models has been used to obtain a phenomenological view rather than quantitative information about these structures. A progressive way has been thought to make a comprehensive an practical approach to this kind of structure, characterized by its ability to offer displacements of long range. We propose like a first steep a rough simulation through elastic member models or elastic-surface models. An iterative process starts, based on visualizations through different peripheric devices (screened and plottered graphic outputs). This first steep ends by the formulation of an optimum geometric performances of the structure. The resulting geometry serves like a source structure for a more accurate calculus achieved by the Finite Element Method. Discretization of the continues structure is carried out in a network of tiny triangular elements. Finally, 3-D realism techniques has been used to represent the form adopted or stress field calculated or both at the same time, by an adequate use of the color attributes of the finite elements.