In the initiation phase of complex construction projects, developers need an early access to a reliable database. Such as gross floor area, usable net area, resulting workspaces, costs, etc. In conventional planning processes, the data basis only successively builds up. Our methodology combines parametric design with modular planning. We weave two methods that are based on a fundamentally digital conceived design logic. Building up on each other they develop their full potential. It emerges an early on reliable basis that enables for a profound decision on the further development of the project.