Reverse Loading and Unloading Trucks in Warehouses

Reverse Loading and Unloading trucks- FlexSim Simulation

Reverse Loading and Unloading Trucks in FlexSim simulation

Truck transportation and warehouse

With a variety of trucks at manufacturers’ disposal, truck transportation and warehousing industries are a significant link between manufacturers and consumers.

For Logistics providers and Warehouse managers, FlexSim plays a vital role in visualizing the warehouse operations using 3D simulation. A 3D Warehouse Simulation helps you to understand the system or predict the outcome of changes.

Basically, during simulation exercises, the requirements from the industry are to imitate the realistic process of loading and unloading trucks at the docking stations. However, FlexSim does not have an option by default to make the truck move in the reverse direction and this is a problem. A solution as explained in the blog helps simulate the reverse movement and thus make the simulation match to real movements.  

This post will explain designing of a 3D model for demonstrating reverse parking of a truck using FlexSim.

The Aim of this model

Build a 3D model using FlexSim to demonstrate reverse parking of a truck.

Components Needed to build the model

1) From the 3D library

  • AGV network- Allow the AGV to move in a preferred path.
  • DockDoor – Use to store the materials from the truck.
  • ControlPoint1- Truck Origin Point.
  • ControlPoint2- Drop-off point.
  • ControlPoint3 – Destination.

2) From the Process flow library

Below are some functionalities from the Library for helping you with building the model.

  • Source – Creating a token
  • Create Truck – Creating a 3D model of the truck
  • Custom Code – Writing the code you require.
  • Assign CP- For creating a Label in Token
  • Travel – Sets the truck on the travel route to the finalized location.
  • Unloading –Sets the time you require for unloading trucks.
  • Create Box – For creating a Box in the dock door at the time of unloading the truck.
  • Sink – Destroys the token.

Steps to build the model

In the FlexSim 3D simulation model

  1. Using the Drag and Drop option from the Fixed Resource Library, create a DockDoor (Queue).
  2. Drag and drop a queue and label it as the DockDoor.
  3. Create an AGV path and acquire the control point for the location reference from the AGV library. You have the option of creating a straight path, curved path as well as joining the path using the option under the AGV library.
  4. Create a one-way AGV path between the Source and Destination. Also, create a two-way path from the drop-off point. Ensure these two paths crossover and the end point of the two-way path is not on the one-way path. (Refer to the diagram below )
  5. Use 2 curved paths (Unidirectional) to create the below paths.
    • A path from the source to the Drop-off point.
    • A path from the Drop-off point to the destination.
  6. For the Truck’s starting point in the model, create a control point (Controlpoint1) near the Source point in the AGV network.
  7. Also, create a control point (Controlpoint2) near the Drop-off Point in the AGV network. This thereby acts as the point for unloading the trucks in the model.
  8. Finally, create the third control point (Controlpoint3) near the Destination in the AGV network. This point acts as the Exit Gate for the truck in the model.
loading and unloading trucks using flexSim simulation
The model without a curved path
loading and unloading trucks with FlexSim Simulation
The model with curved path

In Process flow

  1. From ‘Token creation’ library create Schedule Source and use it to create a Token in the process flow.
  2. Configure the Schedule Source to create one token by setting the ‘Quantity’ to ‘1’.
  3. From the ‘Object’ library, using Create Object create a truck.
  4. Open the Create Object and set the ‘Quantity’ as Under ‘Create in’ refer the Control point, Under ‘Assign to’ set a label name called Truck.
  5. From the ‘Basic’ Library, use the get Assign Label and assign a label to the control points.
    DropoffpointCp is the label for ‘ControlPoint2’, DestinationCp for ‘ControlPoint3’.
  6. From ‘Task Sequence’ library use the Travel option for making the truck starts from the Origin point to Drop-off Point.
  7. Open the Travel and set the destination as DropoffPointCp.
  8. From ‘Task Sequence’ library set the Time Required for unloading the items under Delay.
  9. Open the Delay by double-clicking it.
    • Under ‘Task Executor’ tab set the Truck label.
    • Under ‘Delay Time’ set the time to Unloading.
    • Finally, under ‘State’, set the state as Unloading.
  10. From the ‘Object’ library create the DockDoor using Create Object.
  11. Open the Create Object and set the ‘Quantity’ as Under ‘Create in’. Refer to the control point. This tells the truck to unload the items in DockDoor, also set the label name as Item.
  12. From the ‘Task Sequence’ library set Travel. This command will make the truck to start the travel from Drop-Off Point to the destination.
  13. Open the Travel set the Truck label Under” Task executor and under the ‘Destination’ set DestiantionCp
  14. From the ‘Basic’ library get a Sink to destroy the token created.
  15. Now you can run the model, and the truck will travel in a reverse direction to drop the items as it does in the real-time.


Using the above simulation model, your client can now have a realistic version of the truck movement. Enhancements like these make Simulation accurate, powerful and more reliable.

Check out this blog for more interesting information on FlexSim Simulation mainly in the Supply Chain simulation area. For more information on the services of FlexSim, please do visit our page:

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