Frequently asked questions#

This section provides answers to frequently asked questions.

How do you report issues?

You can report issues with PyMechanical, such as bugs, feature requests, and documentation errors, on the PyMechanical repository’s Issues page.

If you want to ask more open-ended questions or are seeking advice from experts in the community, you can post on this repository’s Discussions page.

How is PyMechanical positioned with respect to other related Ansys tools?

When you want to automate or extend Ansys Mechanical, you should consider these tools:

ACT in Mechanical
Scripting in Mechanical
PyMechanical

Although all of these tools work best in interactive mode, there is increasing support for batch mode. You can use the first two tools from either Ansys Workbench or from standalone Mechanical.

ACT in Mechanical

In Mechanical, ACT is a customization framework. When specific features are missing, you can add them using ACT. Of course, some of those missing features might be automations or scripts of existing features. But, in many cases, they can be new capabilities, such as extensions to Mechanical’s data model, the ability to connect to callbacks, and even integrations of external solvers.

Scripting in Mechanical

The Python scripting capability in Mechanical was born out of the same development that brought ACT to Mechanical. This tool provides the same APIs as those used for PyMechanical but can only be run by Mechanical. While they use IronPython 2.7 by default, recent Mechanical versions provide a feature flag for scripting in CPython 3.x. Mechanical’s intuitive user interface for scripting, the Mechanical Scripting View, provides script recording, autocomplete, and a snippet library. However, it is possible to use this tool in batch mode without the Mechanical user interface.

PyMechanical

PyMechanical allows you to write Python scripts outside of Mechanical, with tight integration with other open source modules and Ansys products. With this tool, you bring your own Python environment, which may contain other modules and tools. There is no dependency on opening the Mechanical user interface.

What is the relationship with Ansys Workbench?

Ansys Workbench is a no-code environment to set up analysis systems that can be linked together. It is part of the Ansys family of software tools for process automation and design exploration. This family includes Ansys OptiSLang, which may be a more natural fit for integration with PyMechanical. The most popular app within the Workbench environment is Mechanical, and for many years, Workbench was the only environment you could run Mechanical from.

Because Workbench is a no-code environment, a lot of the complexity around managing data transfer between Ansys apps and running parametric studies is hidden. PyMechanical and PyAnsys libraries more broadly give you much more control over your process automation and design exploration. However, eliminating Workbench means that you miss out on what it handled under the hood.

How do you restart a script?

If you have trouble terminating a simulation, you do not have to close Python, reopen it, and clear all previous data, such as the mesh, using this code:

import sys

sys.modules[__name__].__dict__.clear()

Simply exiting Python should clear the solution within Python. This is because stopping the original process means that nothing should be present in a new process.

The way that you clear all data from Mechanical in PyMechanical depends on if Mechanical is a remote session or embedded.

If Mechanical is a remote session, use either the Mechanical.clear() method or exit and restart Mechanical.
If Mechanical is embedded, use the app.new() method.

How do you check if a license is active with PyMechanical?

Information about Mechanical can be printed with remote and embedding mode:

Remote

import ansys.mechanical.core as pymechanical

mechanical = pymechanical.launch_mechanical()
print(mechanical)

Embedding

import ansys.mechanical.core as pymechanical

app = pymechanical.App()
print(app)

The output from the above code will indicate the license being used inside the brackets, next to Ansys Mechanical. If PyMechanical is unable to retrieve any license, the field will be left blank.

With License

Ansys Mechanical [Ansys Mechanical Enterprise]
Product Version:242
Software build date: 06/03/2024 09:35:09

Without License

Ansys Mechanical []
Product Version:242
Software build date: 06/03/2024 09:35:09

Alternatively, once the app is created readonly method can be used to see if license is active. If license is not checked out then it is in read only mode.

Why do I get mechanical-env exception in Linux?

To use the embedded instance on Linux, mechanical-env should be invoked before starting the Python shell or running a Python script.

$ mechanical-env python
>>> import ansys.mechanical.core as mech
>>> app=mech.App(version=42)

$ mechanical-env python test.py