diff --git a/Basic_viewer/include/CGAL/Qt/Basic_viewer.h b/Basic_viewer/include/CGAL/Qt/Basic_viewer.h
index b26ecdd479b..d7e3dcd48cc 100644
--- a/Basic_viewer/include/CGAL/Qt/Basic_viewer.h
+++ b/Basic_viewer/include/CGAL/Qt/Basic_viewer.h
@@ -1480,10 +1480,15 @@ protected:
     if(!m_scene.empty())
     {
       auto& bbox=m_scene.bounding_box();
-      double d=CGAL::sqrt(CGAL::squared_distance
-                          (Local_point(bbox.xmin(), bbox.ymin(), bbox.zmin()),
-                           Local_point(bbox.xmax(), bbox.ymax(), bbox.zmax())));
+      double d=is_two_dimensional()
+              ?2.5
+              : CGAL::sqrt(CGAL::squared_distance
+                           (Local_point(bbox.xmin(), bbox.ymin(), bbox.zmin()),
+                            Local_point(bbox.xmax(), bbox.ymax(), bbox.zmax())));
       // std::cout<<"Length of the diagonal: "<<d<<std::endl;
+      // std::cout<<"width: "<< this->width() <<std::endl;
+      // std::cout<<"height: "<< this->height() <<std::endl;
+
       m_size_vertices=1.5*d;
       m_size_edges=d;
       m_size_rays=m_size_edges;