Python Environments
Use Preferences → Python → Manage Python Environments to create a Python environment and manage its packages. Helios can install a managed interpreter without a separate system Python installation. You can also select an existing Python 3.10+ executable in Preferences.
Create and Select
| Step | Action |
|---|---|
| 1 | Open Manage Python Environments and use the create button beside Environments. Hover over an icon to see its action. |
| 2 | Choose a name and Python version supported by your script’s packages. The dialog offers Python 3.10 through 3.14. |
| 3 | Choose the default packages or a requirements file supplied by the script author. |
| 4 | Allow Helios to install its package manager when prompted, then wait for the final installation result. Show Details displays progress and errors. |
| 5 | Select the environment and click Use Environment. Close the manager and confirm Preferences with OK to save the interpreter selection. |
| 6 | Start or restart CV Python with the intended script and check its status. |
Clicking an environment in the list only displays its details. It does not select that environment for scripts. Accepting the prompt to use a newly created environment saves that selection immediately.
Use a distinct name for a new project. Replacing an existing environment requires confirmation and replaces that environment’s installation.
Manage Packages
The selected environment shows its Python version, validity, folder, and installed packages.
- Add Package... installs a package by name, optionally with an exact version or version constraint.
- Select package rows to update or uninstall them with the buttons beside Installed Packages.
- Filter packages... searches names and versions. Packages hidden by a filter are removed from the selection.
- Requirements → Import requirements file... replaces the environment’s requirements file and offers to install it.
- Install from requirements installs the listed requirements while retaining unrelated installed packages.
Stop CV Python, CV C++, and Engine Builder work using an environment before installing, updating, or removing its packages, and wait for stopping to finish. A different unused environment can still be managed.
Wait for each operation to finish before starting another. The progress indicator does not represent a package-installation percentage; use Show Details to inspect progress. Install packages into the environment selected by Helios, especially when several Python installations are present.
Environment Files
A .henv file describes an environment; it is not an installed Python environment. For example:
{
"name": "my-cv-project",
"python": "3.11",
"packages": ["numpy", "opencv-python", "pywin32"]
}Use the package versions required by the script author. A minor version such as "3.11" lets the installer choose an available patch; an exact version such as "3.11.14" requests that patch. Changing a .henv file does not update an environment that has already been created. Use Python 3.10–3.14 for definitions intended for both Helios installation and Online Resources publishing.
Installing a definition from Online Resources or through MCP does not automatically change the interpreter selected in Preferences. Select the installed environment explicitly before using it.
Troubleshooting
- Installation failed: expand Show Details and check the Python version, package constraints, internet connection, and free disk space. Some packages do not yet support the newest Python versions.
- Import error: confirm the required package is installed in the selected environment, then restart the script.
- Environment appears but is invalid: wait for the operation’s final result. A folder or list entry alone does not confirm that packages installed successfully.
- Wrong interpreter: click Use Environment, confirm Preferences with OK, and restart the CV tool.
- MCP installation window was closed: closing that progress window does not cancel installation. Inspect the operation before starting it again.
Managed environments keep dependencies separate. They do not sandbox scripts; run scripts and install packages only from sources you trust.