In this paper, alternative approaches to structure the parametric geometry in relation to information on various performances are described and exemplified. They relate to different levels of knowledge that concern the performances considered in the process and which are available to the designer while the parametric model is being set. A theoretic framework embeds the different approaches, for which the use of parametric modelling is structured in three phases: strategy-definition; model-building; and solution-assessment. The phases and their interrelations are discussed. Finally, four case studies are presented, focusing on the relation between the knowledge available in strategy-definition and the exploration occurring in solution-assessment.