diff --git a/3D-OpenGL-Rendering-Engine.md b/3D-OpenGL-Rendering-Engine.md
index 30213c5..17ee58d 100644
--- a/3D-OpenGL-Rendering-Engine.md
+++ b/3D-OpenGL-Rendering-Engine.md
@@ -6,6 +6,8 @@ Run the simulator as follows (do not forget to set the absolute paths in `opengl
 
     roslaunch esim_ros esim.launch config:=cfg/opengl.conf
 
+At this point, the simulator should be running, however by default it does not show any visualization.
+
 To visualize the output of the simulator, you can open `rviz` (from a new terminal) as follows:
 
     roscd esim_visualization