Abstract A computer-aided design program for cable reinforced membrane structures is described. The program makes extensive use of interactive computer graphics techniques for data entry and visual feedback on the current status of the design. Nonlinear finite element analysis is used as the basis of design. Routines are provided for automated generation of finite element meshes using discrete transfinite mappings; solution of the initial equilibrium problem through least squares force adjustment methods, iterative shape smoothing, or nonlinear displacement analysis; and nonlinear stiffness analysis including frictional slip behavior between membrane material and reinforcing cables. The program is capable of handling both pretensioned and air-supported structures. The overall design approach and structure of the program are emphasized.