Your first run

On this page, you run a complete program on your robot, and learn to use the Erebus control window. You need Erebus installed and your robot.

The Erebus folder

These are the main folders of the release you downloaded:

Folder	Contents
game/worlds	The worlds (.wbt files). Open one of them to start.
game/logs	The game logs written at the end of each game
player_controllers	Example controllers

The control window

1. Open game/worlds/world1.wbt in Webots.
2. Webots opens the Erebus control window (the robot window of the Main Supervisor) in your web browser. This is where you load your program and run the game.

Part	Use
Left LOAD (laptop icon)	Loads the controller program of your robot
Right LOAD (robot icon)	Loads your robot (.json file)
TOGGLE REMOTE	Lets a program running outside Webots control the robot. See Remote Controller.
Docker path	Folder with a Dockerfile, to run your controller in a container with the Docker button next to the play button. See the erebus-dockerfiles repository. This is optional.
Settings	Links and options, explained below
Worlds	Changes to another world
Reset	Resets the loaded program and the game
Give up!	Ends the game
Timers	The game time, and below it the real-world time in brackets. The game ends when either of them reaches 0.
Calculator	The current score

Run a program

Download maze.py, a complete program that drives the robot around the maze. It is the program you will write yourself in Navigate the maze.

1. Open game/worlds/world1.wbt.
2. Load your robot with the right LOAD button, if you have not done so yet. The world reloads with it.
3. Load maze.py with the left LOAD button. When the program is loaded, the button turns into an orange REMOVE button.
4. Press the start button. The robot appears in the world and starts moving.
5. To stop the robot temporarily, press the pause button.
6. If the robot is stuck, press the restart button to trigger a lack of progress. It moves the robot back to the last checkpoint it reached, and costs 5 points.
7. Press the Reset button to reset the loaded program and the game in progress. Reload the world if you want to run it again after a game has ended.

The program needs OpenCV, which you installed with the other Python libraries. Messages from your program, and errors, appear in the Webots console.

While the game is running, the score history appears at the bottom of the window. It tells you exactly why you gained or lost points, so it is the best tool to check your program.

At the end of the game, the same information is saved in the game/logs folder.

Using other worlds

Press Worlds to change to another world. Each world has a thumbnail, and you can also add your own, made with the World Editor.

The worlds included in Erebus v26.1 are:

World	Purpose
world1.wbt, world2.wbt	Example worlds. world2.wbt includes Area 4.
world3.wbt, world4.wbt	Larger example worlds, which also include fake victims
mapping_example_1.wbt to mapping_example_3.wbt	Worlds to test your mapping. See Mapping.
NewPassages.wbt	Example of the passages between areas

Settings

Setting	Use
Keep controller/robot files	Keeps your program and robot loaded when the world is reloaded
Disable automatic LoP	Stops the automatic lack of progress after 20 seconds. Only for debugging.
Automatic camera	Makes the view follow the robot
Recording	Records the game as a video
Keep remote controller on	Keeps TOGGLE REMOTE on when the world is reloaded
Enable debugging	Prints extra information in the Webots console, for example why a wall token report was rejected

The links at the top lead to the changelog and to tools for making worlds and robots. To make worlds with the 2026 rules, use the World Editor.

Manually move the robot where you want it to go

When you click a robot in the simulation window, red, green and blue arrows appear. Drag these arrows with the mouse to move the robot to any position. Note that the robot is not displayed until the program has started.

Next

You have seen a robot explore on its own. Now learn to program it yourself: start with Your first program.