How to install additional Python modules in PLAXIS

Application	PLAXIS 2D PLAXIS 3D
Version	PLAXIS 2D CONNECT Edition V20 PLAXIS 3D CONNECT Edition V20
Date created	13 October 2020
Date modified	13 October 2020

When using the PLAXIS scripting environment it is common to use Python modules allowing for extending the functionality of a Python script. An example of a Python module is easygui, which offers an easy-to-use interface for simple GUI interaction with the user.

With PLAXIS CONNECT Edition a PLAXIS-Python Distribution is provided and stored in a dedicated versioned location within the ProgramData folder (see release notes for 2D and 3D), including various Python modules.

This allows both PLAXIS 2D and PLAXIS 3D applications to access this shared distribution when using Python Scripting facilities, keeping all the modules up to date and fully compatible with PLAXIS.

This article will explain the available options in PLAXIS applications on how to install and use any Python modules required when scripting.

Using the modules in the installed PLAXIS-Python Distribution

With the release of PLAXIS CONNECT Edition V20 Update 3, a separation is made of the deliverable Python environment: one that can be used for user-created Python scripts and the editor, and one trimmed down environment intended for all PLAXIS extensions implemented using Python language, e.g. the PLAXIS 2D to 3D converter and the structural Coupling tool, the parameter optimization tool for UDCAM-S constitutive model.

The PLAXIS-Python Distribution includes various modules, such as easygui, matplotlib, numpy, pyperclip and it is placed in a dedicated versioned location within the ProgramData folder.
By default, this is: C:\ProgramData\Bentley\Geotechnical\PLAXIS Python Distribution V1

Using a custom Python distribution

With PLAXIS CONNECT Edition V20 Update 3 it is possible to configure PLAXIS to use a custom Python version, which is installed in the computer. To do so, the following steps are required:

1. Start the PLAXIS Input as administrator from Windows Start menu.
   This is important in order to have proper rights to proceed with installing the required PLAXIS modules in the custom Python directory.
2. Go to menu option Expert > Python > Configure Python Interpreter, select the option Use the following Python interpreter and browse to the custom Python distribution folder
3. Select the option to Install required components.
   This will make sure all required modules and files for PLAXIS scripting environment are installed in the custom Python directory.
4. A popup window will provide information on the progress of the installation of the Python packages.

Figure 1. Configure and use a custom Python distribution

Note: changing to a different Python interpreter means that all options for Python, such as Run Python Script/Tool, Interpreter, Editor will use the custom Python interpreter as configured.

Any errors encountered during the installation of the required components may be linked to the custom Python version.

Install Python modules in the PLAXIS-Python Distribution

It is possible to install various Python modules that are not already available in the PLAXIS-Python Distribution via the Command prompt window.

To do so, the following steps are required:

1. Start the PLAXIS Input as administrator from Windows Start menu.
   This is important in order to have proper rights to proceed with installing/updating any Python modules in the local Python directory.
   Note: you can also directly launch the Command prompt of Windows, and then move to step #3.
2. Go to menu option Expert > Python > Command prompt
   This will open the familiar Windows Command prompt with the PLAXIS set as current directory.
3. If needed, change directory to the PLAXIS-Python Distribution, where the Python packages are installed. This can be done by running the command:
   cd C:\ProgramData\Bentley\Geotechnical\PLAXIS Python Distribution V1\python\Lib\site-packages
4. In the Command prompt you can now install any new Python modules using the command shown in the example below.
   For instance, if you want to install the pandas module:
   python -m pip install pandas

Figure 2. Installing pandas module using the PLAXIS Command prompt

Note that the installation of a Python module may require an updated version of another Python module. This may affect other modules that are available in the PLAXIS-Python Distribution, therefore, make sure to understand the changes made during the installation of any Python module.