Abstract. We present a new application for graph drawing in the context of graphical model-based system design, where manual placing of graphical items is still state-of-the-practice. The KIELER framework aims at improving this by offering novel user interaction techniques, enabled by automatic layout of the diagrams. In this paper we present extensions of the well-known hierarchical layout approach, originally suggested by Sugiyama et al. [22], to support port constraints, hyperedges, and compound graphs in order to layout diagrams of data flow languages. A case study and experimental results show that our algorithm is well suited for application in interactive user interfaces.