cutelolly / hycohanz

Interact with ANSYS HFSS via the Windows COM API using Python.

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hycohanz is an Open Source (BSD license) Python wrapper interface to the ANSYS HFSS Windows COM API, enabling you to control HFSS from Python. hycohanz simplifies control of HFSS from Python for RF, microwave, and antenna engineers.

Minimal Example

import hycohanz as hfss

[oAnsoftApp, oDesktop] = hfss.setup_interface()

raw_input('Press "Enter" to quit HFSS.>')


del oDesktop
del oAnsoftApp

Dozens more examples are included in the examples directory of the source distribution.

Quick Install

Installation is easy if you already have HFSS, Python, and the pywin32 Windows extensions for Python:

  1. Download the .zip file from Github.
  1. Unzip to a convenient location.

  2. At the Windows command shell prompt, run:

    > C:\Python27\python install

See Detailed Installation if you don't already have Python installed.

Problems, Bugs, Questions, and Feature Requests

These are currently handled via the hycohanz issue tracker

This issue tracker is useful if you

  • run into problems with installing or running hycohanz,
  • find a bug,
  • have a question,
  • would like to see a feature implemented.

Of course, you can also email me privately.


hycohanz provides convenience functions for the following:

  • Starting, connecting to, and closing HFSS
  • Creating design variables
  • Manipulating HFSS expressions
  • Creating 3D models using polylines, circles, rectangles, spheres, etc.
  • Querying objects and groups of objects
  • Object manipulation via unite, subtract, imprint, mirror, move, cut, paste, rotate, scale, sweep, etc.
  • Assigning boundary conditions
  • Manipulating projects and designs
  • Creating analysis setups and frequency sweeps


Dozens of examples are included in the examples directory of the source distribution.


hycohanz is pre-alpha software and is in active development. The hycohanz function interfaces can be expected to change frequently, with little concern for backwards compatibility. This situation is expected to resolve as the project approaches a more mature state. However, if today you require a stable, reliable, and correct function library for HFSS, unfortunately this library is probably not for you in its current form.

See Also

scikit-rf: An actively-developed library for performing common tasks in RF, providing functionality analogous to that provided by the MATLAB RF Toolbox. If you're working with RF or microwave you should consider getting it.

PyVISA: Enables control of instrumentation via Python.

matplotlib: Excellent Python 2-D plotting library.

numpy: Fundamental functions for manipulating arrays and matrices and performing linear algebra in Python.

scipy: Builds upon numpy to enable MATLAB-like functionality in Python.

sympy: Implements analogous functionality to the MATLAB Symbolic Toolbox.


A zip file of the development branch can be downloaded from

Of course, one can also pull the source tree in the usual way using git.


Several basic examples can be found in the examples directory.

Most wrapper functions are documented with useful docstrings, and in most cases their interfaces tend to follow the HFSS API fairly closely.

For best use of this library you should familiarize yourself with the information in the HFSS Scripting Guide, available in the HFSS GUI under Help->Scripting Contents. The library is intended to be used in consultation with this resource.

If the docstrings and examples are not sufficient, you will find that many functions consist of five or fewer lines of simple (almost trivial) code that are easily understood.

Frequently Asked Questions

Q:Why not write scripts using Visual Basic for Applications (VBA) or JavaScript (JS)?
A:I've found that programming in Python is generally much, much easier and more powerful than in either of these languages. Plus, I've generally found that Visual Basic scripts run inside HFSS tend to break without useful error messages, or worse, crash HFSS entirely. hycohanz can also crash HFSS. But when it does, the Python interpreter gives you a nice stack trace, allowing you to determine what went wrong.
Q:Why use Windows COM instead of .NET?
A:As I understand it, the Visual Basic examples in the HFSS Scripting Guide use Windows COM, so that's what I use. If you're using IronPython, then accessing .NET resources should be trivial. However, I don't use IronPython since I make extensive use in my daily work of numpy, scipy, matplotlib, h5py, etc., and IronPython has had issues integrating with these tools in the past.
Q:Why not metaprogram VBA or JS? Then I could use this library on Linux.
A:That was my initial approach, because I wanted cross-platform capability. Compared to the Windows COM approach, it's a lot more time-consuming, and it has all of the drawbacks of the first question.
Q:Why did you use Python instead of MATLAB?
A:I'm a recent convert to Python, so I now use Python in my daily workflow whenever it's convenient (that means about 99.9% of the time). Python gives you keyword arguments, which helps keep the average length in characters of a hycohanz function call to a minimum, while minimizing implementation overhead compared to MATLAB.
Q:Why not skip the HFSS interface entirely and directly emit a .hfss file? Then I could use this library on Linux.
A:I've also considered this approach. As you may know, .hfss files are quasi-human-readable text files with a file format that could in principle be reasonably parsed and emitted. However, the expected implementation effort would have been quite a bit higher than I wanted. Not to mention that the format is not (to my knowledge) static, nor is it publicly specified or documented. Thus, an implementation of this approach would be expected to be fragile, crash HFSS frequently, and leave non-useful error messages.


Often one finds that this library is missing a wrapper for a particular function. Fortunately it's often quite easy to add, usually taking only a few minutes. Most of the time it's a quick modification of an existing function. Many functions can be implemented in five lines of code or less. If you do add a feature to the code, please consider contributing it back to this project.


Interact with ANSYS HFSS via the Windows COM API using Python.

License:BSD 2-Clause "Simplified" License


Language:Python 100.0%