Update README.md

Author: cybergalactic

README.md

@@ -4,7 +4,7 @@ The Python Vehicle Simulator is a supplement to the Matlab MSS (Marine Systems S
 
  Source files:
  /src/python_vehicle_simulator/ 
-  main.py - MAIN program 
+  main.py - MAIN PROGRAM
   control.py - feedback control systems
   gnc.py - generic GNC functions
   guidance.py - guidance functions 
@@ -21,7 +21,11 @@ The Python Vehicle Simulator is a supplement to the Matlab MSS (Marine Systems S
   shipClarke83.py - Ship, linear maneuvering model specified by L, B and T using the Clarke (1983) formulas
   supply.py - Offshore supply vessel controlled by tunnel thrusters and main propellers, L = 76.2 m
   tanker.py - Tanker, rudder-controlled ship model including shallow water effects, L = 304.8 m
-
+  
+ Animated GIF:
+ /src/python_vehicle_simulator/ 
+  3D_animation.gif - 3D animation file which can be opened in a web browser
+  
 For more information about mathematical modeling of marine craft and methods for guidance, navigation and control, please consult:
 
 T. I. Fossen (2021). Handbook of Marine Craft Hydrodynamics and Motion Control. 2nd. Edition, Wiley.