Fillets: Cues for Connections in Focus+Context Views of Graph-Like Diagrams

We apply fillets — smoothing of sharp angles at the joints — between the connections and nodes of graph-like diagrams. In situations where the graph layout is constrained, e.g. Focus+Context views or views where the coordinates of the nodes are informative, fillets can clarify the relationships considerably without altering the layout. A visual search experiment supports our hypothesis that with fillets it is considerably easier to perceive nodeconnection structures. We discuss algorithms with different tradeoffs for flexibility and performance for rendering these connections in a single pass using OpenGL.