CCVisu: A Tool for Visual Graph Clustering and General Force-Directed Graph Layout The tool CCVisu is a light-weight tool for force-directed graph layout. The tool reads the input graph from a file in RSF (Relational Standard Format), which is a standard text format for relations. The layout of the graph is computed using standard techniques from force-directed layout. The tool supports several energy models, which can be selected by setting command line parameters. The weighted edge-repulsion LinLog energy model (default) is good for producing layouts that fulfill certain clustering criteria. The Fruchterman Reingold energy modelis good for producing layouts that fulfill certain esthetic criteria like uniform edge length. The minimizer is based on the Barnes-Hut-Algorithm. CCVisu saves the resulting layout in the file formats SVG, VRML, the standard text format for relations RSF, or it displays the layout on the screen