This paper introduces a design methodology and a toolkit developed as a parametric CAD program for configurative design of architectural plan layouts. Using this toolkit, designers can start plan layout process with sketching the way functional spaces need to connect to each other. A tool draws an interactive bubble diagram and a set of tools reveal feasible geometric interpretations of the proposed bubble diagram in terms of plan layout graphs. Offering real-time Space Syntax analyses at the same time, the tools provide feedback on the spatial performance, which is translatable into the likely social performance of the plan layout patterns.