In the aerospace industry, stretch forming of heat-treatable aluminum sheet is widely used to produce complicated products, such as doubly curved surfaces. Such complicated surfaces are formed in multiple strain steps combined with intermediate anneals because of strain hardening of the sheet. The product is produced by moving the grippers of the stretch forming machine. The Numerical Controlled (NC) program to move the grippers and optimize the amount of strain in each run, is made with a trial and error method. This is not only an expensive method but also a random method since the material properties fluctuate strongly. This latter results in serious surface problems in case of polish skin parts, such as orange peel. Therefore, simulation of the stretch forming process is of great importance to predict the strain distribution in complex products, to find out the limits of the forming process, to optimize the die, and to optimize the number of runs. Fokker uses a commercially available simulation package in combination with an implicit FEM code, DieKa, to simulate stretch forming parts. In this research the stretch forming process is simulated. By varying the position of the die and the design of the die, the strain distribution in the sheet is minimized to obtain a minimum number of runs with an optimal stretch forming path. With this method a stable production process is established that is not influenced by material fluctuations.