Setting up the Simulator

There are three key components you will need in order to be able to use the simulator:

• Webots, the platform which runs the simulation
• Python, the interpreter for the your robot code
• The world simulation, which includes the SR API for use in the simulator

Webots

Webots is a free open-source robot simulator. It is the program which runs the simulation.

You need to download Webots from here and install it.

The current supported version is R2023b.

Troubleshooting: performance

The default settings work for most users however if you are using a less powerful computer or one without a dedicated graphics card (as is the case on many laptops), you may wish to adjust the graphics settings to enable the simulation to run faster.

If you find that the simulation runs very slowly we suggest disabling both Ambient Occlusion and Shadows. These should not affect the behaviour of the simulation, only the rendered visuals.

To do this on Windows, open webots and go to the menu Tools → Preferences → OpenGL, then set Ambient Occlusion to “none” and check the box next to “Disable shadows”.

To do this on Mac, open webots and go to the menu Webots → Preferences → OpenGL, then set Ambient Occlusion to “none” and check the box next to “Disable shadows”.

Python

You will also need Python installed. If it is not already installed this can be downloaded and installed from the Python website.

We recommend using Python 3.11 as it is the newest supported version and is the version which is used on your physical robot. The most recent version of Python (3.12), which is the default download, is not yet supported by Webots.

Python libraries

There are a small number of external libraries which are available on the physical kit that may be useful in the simulator. If you want to use these in your code you will need to install these yourself.

Once you have downloaded the simulation, the libraries can be installed with the following command in a terminal.

pip install -r competition-simulator-<version>/libraries.txt

Troubleshooting: setting your version of Python

Sometimes Webots will not automatically detect your installed Python in which case it will need to be set manually. When this happens Webots will print errors to its console and your robot will not move.

You will need the full path to the version of Python that you want to use. This will vary based on the system you have. One way to find the path is by launching Python and running the following code:

import sys
print(sys.executable)

Once you have the path you need to enter this into the Webots settings.

To do this on Windows, open webots and go to the menu Tools → Preferences → General → Python command and enter the path in that box. Your Python path is likely similar to C:\Users\<USERNAME>\AppData\Local\Programs\Python\Python311\python.exe when using Python 3.11, where <USERNAME> is your login.

On Mac you can set the path to the Python version to use via Webots → Preferences ⌘,. Your Python path is likely similar to /Library/Frameworks/Python.framework/Versions/3.11/bin/python3 when using Python 3.11. If you installed Python using Homebrew, it will be in /opt/homebrew/bin/python3.11 (or /usr/local/bin/python3.11 on an Intel-based Mac)

If you’re still having problems, ask for help in Discord.

The world simulation

The world simulation we provide defines the environment that contains the simulated arena and robot as well as the SR API for use in the simulator.

1. Create a directory, perhaps called simulation where you will store your robot code.
2. Download the simulation, the latest version is sr2024.2, released on 2024-02-04.
3. Unzip the simulation as a folder inside the folder you created in the first step:

    simulation
    ├── competition-simulator-<version>
    │   ├── ...
    │   └─ libraries.txt
    │   └─ worlds
    │       └── Arena.wbt
    └── robot.py
   

   If there is not an existing robot.py an example one will be created when the simulator first runs.

4. Open the Webots IDE, then use that to open the worlds/Arena.wbt file.

You may receive a warning about your computer’s GPU not being good enough, which can be ignored.

Updates

Occasionally, we may release an update to the simulation. To update, you will need to delete the competition-simulator-<version> folder and replace it with the new version that can be downloaded using the above link.

If you need a specific version of the simulator, or want to see what changes have been made with each version, please see the list of releases.