A method of interactively determining at least one optimized design candidate using an optimizer, the optimizer having a generation algorithm and an objective function, the optimized design candidate satisfying a design problem definition, comprises generating design candidates based on the generation algorithm. The generated design candidates are added to a current set of design candidates to form a new set of design candidates. The design candidates are evaluated based on the objective function so that design candidates can be selected for inclusion in a preferred set of design candidates. The current state of the optimizer is presented to a designer for interactive examination and input is received from the designer for updating the current state of the optimizer. These steps are repeated until a stopping criterion is satisfied.