Building models of a complex system such as an ecosystem or a chemical plant is an arduous task that can take several person months to complete. One rarely knows the scope of the model, its assumptions and claims, at the outset of the task, let alone how to state those in a formal language. To make this task manageable, modelers start at the whiteboard – by making free-form drawings that capture their current understanding of the studied system. These drawings need not conform to any particular ontology and may lack internal coherency or consistency. Nevertheless, such drawings can help organize one’s thoughts and can capture key participants and relationships in the dynamic system. We argue that these free-form drawings facilitate the modeling process, based on evidence from modeling in practice. We analyze the relationship between free-form drawings and formally encoded models. We then suggest how to exploit these relationships to develop a modeling environment that supports a tighter integration between conceptual and detailed modeling.