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🛠️ Do you have any trouble?

Don’t worry, we’re here to help! Below are solutions to some common issues you might encounter when using Webots.

⚠️ Problem: "python.exe" was not found.

When running your controller, you might encounter the following error:

WARNING: "python.exe" was not found.
Webots requires Python version 3.9, 3.8, or 3.7 from python.org in your current PATH.
To fix the problem, you should:
1. Check the Python command set in the Webots preferences.
2. Check the COMMAND set in the [python] section of the runtime.ini file of your controller program, if any.
3. Fix your PATH environment variable to use the required Python 64-bit version (if available).
4. Install the required Python 64-bit version and ensure your PATH environment variable points to it.

✅ Solution: Step 1: Check if Python is Installed

Run the following command in your terminal to check the Python version:

python3 --version

or

python --version

If Python is not installed or if you need a specific supported version (3.7, 3.8, or 3.9), download and install it from the official Python website.

Step 2: Set Python Path in Webots Preferences

  • Open Webots.
  • Go to Tools → Preferences.
  • Under the General tab, locate the Python command field.
  • Set this field to the correct Python path.

tool-pref python

You can find your Python installation path using these commands:

For Linux/macOS:

To locate your Python executable, run:

which python3

or for a specific version:

which python3

Typical paths might be:

  • /usr/bin/python3
  • /opt/homebrew/bin/python3

For Windows: Use:

where python

This typically returns paths like:

  • C:\Python39\python.exe

Ensure this path is correctly set in Webots Preferences.

⚠️ Problem: "ikpy" module is not installed.

When running your controller, you may encounter this error:

The "ikpy" Python module is not installed. To run this sample, please upgrade "pip" and install ikpy with this command: "pip install ikpy"

✅ Solution: Install the required module in the correct Python environment by executing these commands in your terminal:

pip install --upgrade pip
pip install ikpy

Same procedure to do for any other libraries, modules that needs to be installed such as matplotlib, numpy,…