private void initRenderer() {
   if (renderer3d) {
     nodeRenderer = new Renderer3D();
     edgeRenderer = new Renderer3D();
   } else {
     nodeRenderer = new Renderer2D();
     edgeRenderer = new Renderer2D();
   }
   nodeRenderer.initRenderer(model.getNodeFont());
   edgeRenderer.initRenderer(model.getEdgeFont());
 }