// set up the renderers
// draw the nodes as basic shapes
Renderer nodeR = new ShapeRenderer(20);
// draw aggregates as polygons with curved edges
Renderer polyR = new PolygonRenderer(Constants.POLY_TYPE_CURVE);
((PolygonRenderer)polyR).setCurveSlack(0.15f);
DefaultRendererFactory drf = new DefaultRendererFactory();
drf.setDefaultRenderer(nodeR);
drf.add("ingroup('aggregates')", polyR);