A building’s facade design has significant impact on the daylighting performance of interior spaces. This paper presents a tool based on a genetic algorithm (GA) which facilitates exploration of facade designs generated based on illuminance and/or glare objectives. The method allows a user to input an original 3d massing model and performance goals. The method assumes that the overall building form remains the same while the facade elements may change. Ten facade parameters are considered, including glazing materials and geometric characteristics of apertures and shading devices. A simple building information model (BIM) is used to automatically generate a 3d model of each individual. Results from single and multi-objective case studies are presented to demonstrate a successful goal-driven design exploration process.