Main/dev:

See the Installation Instructions for instructions on installing pyNastran.

v1.4.1

Download GUI (latest is from 2024/3/25)

Also, check out the:

• 
• Discussion forum (intended for questions about the latest release)
• Developer forum (intended for questions about the main branch)
• Docs
• Code of Conduct
• Contributing

for more detailed information.

Blogs

• Flutter Analysis in pyNastran

Code of Conduct

Everyone interacting in the setuptools project’s codebase, issue trackers, chat room/Discord, and mailing lists is expected to follow the Code of Conduct.

Overview

pyNastran is an interface library to the various Nastran file formats (BDF, OP2, OP4). Using the BDF interface, you can read/edit/write Nastran geometry without worrying about field formatting. Many checks are also performed to verify that your model is correct. Using the OP2 interface, you can read large result files quickly and efficiently. Additionally, you can also extract a subset of the result data and write OP2/F06 result files. For a more detailed list of features, see:

• Features

Using the pyNastran GUI, you can read in Nastran models and quickly view results for a model. While it's no FEMAP/Patran, it can replace many tasks that would otherwise require a commercial program.

News

v1.4.1 has been released (2024/3/25)

This is a mainly a bug fix release. There's also a couple of new acoustic cards and MSC's STRESSA table that were added to fix some errors.

The force/bending moment diagrams have also been improved:

• Loads popup
• Visuals to indicate the location of the cutting planes
• Element ids may also be explicitly limited now
• You can pick the plot x-axis (global x/y/z vs. distance)

See pyNastran release notes for details on the other changes.

v1.4.0 has been released (2024/2/29)

It's been a while since the update, but I've had a more time lately. MSC also provided a copy of MSC Nastran free of charge to help support the project, so modern MSC Nastran support is much better.

Finally, the GUI has received a lot of work recently including:

• Better results selector. Individual displacment and SPC/MPC/Load Vector components are selectable. For solid, plate, and composite stress/strain, nodal or centroidal stress may be shown and various blending methods including nodal averaging is now supported.
• Grid Point Forces are supported in the GUI. They take some getting used to but you can march along a vector and output the section loads in any arbitrary coordinate system.
• Preferences are also now exposed in a json file (vs the registry) and if you find a bug in the new results, you can flip a flag to use the old objects.
• A recent files history to speed up model loading and a whole bunch of other bug fixes.

Programmatics:

• Supports Python 3.9 - 3.12 (later versions of Python requires downloading from github)
• GUI is compatible with VTK 9 and PyQt5/PySide2
• improved testing of old versions of packages
• much improve NX 64-bit and OptiStruct support

BDF:

• fixed CAERO1 paneling bug
• 427 cards supported (up from 405)

OP2:

• 20 new results
• vectorized op2 writing
• model.cquad4_stress is now found in model.op2_results.stress.cquad4_stress. Same goes for other stress, strain, force, and strain_energy components. This will hopefully make things a bit easier find.

GUI:

• grid point forces / section cuts / shear-moment torque plotter
• more dynamic stress/strain results allow for simpler menus
• transient/complex fringe only animations now supported
• recent files support
• greatly expanded preferences menu; many more preferences are saved
• new icons

See pyNastran release notes for details on the other changes.

v1.3.4 has been released (2022/5/30)

This is a bug fix release mainly to address dependency changes:

Programmatics:

• supports Python 3.7-3.10
• support for nptyping 1.1.1-2.0 (removed as a required dependency)
• support for h5py >3.0
• GUI is compatible with PyQt5/6 and PySide2/6 and VTK 7-9

There are also at least 33 bugs fixed and a few features added from the 1.4 release (e.g., pathlib support, subcase limiting in the flutter F06 parser).

See pyNastran release notes for details on the other changes.

v1.3.3 (2020/6/28)

See v1.3.3 for information regarding enhancements.

pyNastran v1.3.2 has been released (2020/4/8)

See v1.3.2 for information regarding enhancements.

v1.3.2-v1.3.0 (2020/4/8)

This result has been superseded by 1.3.2. The PyPi page was fixed.

v1.2.1 (2019/5/24)

I keep saying to myself there's not much to add, but Nastran is huge. Beyond HDF5 support in the BDF, I'm a huge fan of the new ability to keep track of which include file a card came from and write it as a separate file. It's limited in usefulness, but very handy in certain cases. There's a new (still preliminary) superelement capability. I'm far from a superelement expert, but it's probably useful.

The OP2 reader now supports SORT2 along with much improved random results reading. If you're using 60+ GB OP2s, you probably have had issues with RAM usage in the past. With the new ability to dump the OP2 directly to HDF5, this should not be an as much of an issue. It's not 100% implemented, so let me know if you need it for another result.

Regarding the GUI, there are also some new features. Groups work a bit better, but aren't quite perfect. Logging has been dramatically sped up, so the GUI loads faster, and you can load Nastran models even faster if you disable additional results (e.g., element quality).

Finally, Python 2.7 is end of life. Numpy, scipy, and matplotlib have all dropped Python 2.7 support. It's time for pyNastran to as well. The OP2 reader is 30% faster in Python 3.6+ than Python 2.7, so it's not all bad!

Programmatics:

• This is the last Python 2.7 release.
• Dropping Python 3.5 support
• Supports Python 2.7, 3.6-3.7
• GUI is compatible with PyQt4/PyQt5 as well as PySide/PySide2
• improved testing of old versions of packages

BDF:

• 373 cards supported (up from 343)

• added abiltity to write models to separate include files

  >>> model = BDF()
  >>> model.read_bdf(bdf_filename, save_file_structure=True)
  
  out_filenames = {
      bdf_filename : bdf_filename_new,
      include_filename : include_filename_new,
  }
  >>> model.write_bdfs(out_filenames, relative_dirname=None, is_windows=None)
  >>> ifile = model.grids[1].ifile

• HDF5 import/export

  >>> model = read_bdf(bdf_filename)
  >>> model.export_hdf5_filename(hdf5_filename)
  >>> model_new = OP2()
  >>> model_new.load_hdf5_filename(hdf5_filename)

• preliminary superelement support

  >>> model.read_bdf(bdf_filename)
  >>> model.superelement_models[1].nodes

OP2:

• reorganization of random op2 results into op2.results.psd (or ato, no, crm, rms) to aid in finding data

• reorganization of op2 class to reduce number of functions in the object. This affects any custom table reading.

• improved optimization response reading

• limited SORT2 support

• fixed CD transformation bug for BOUGV1 and BOPHIG1 tables

• Improved HDF5 export/import support (e.g., matrices, random results)

• Can optionally save directly to HDF5 instead of numpy (limited).

• Loading OP2s to an HDF5 file to decrease memory usage

  >>> op2_model = OP2()
  >>> op2_model.load_as_h5 = True
  >>> op2_model.read_op2(op2_filename)

OP2Geom:

• HDF5 support
• reading EQEXIN/S, GPT, GPDT, CSTM/S tables (recovery of nodes & coordinate with OP2Geom)
• fixed theta/mcid reading for CTRIA3/CQUAD4
• fixed CQUAD8 bug

GUI:

• sped up HTML logging
• much improved groups menu
• options for Nastran in preferences menu to speed up loading/limit memory usage
• pyNastran BDF pickle reading
• pyNastran OP2 HDF5 reading (not MSC's format)
• visualization when picking nodes/elements
• min/max labels
• highlight menu
• Patran-style colors
• custom force vectors
• AVL support

Known issues:

• Transient Pandas Dataframes will fail for newer versions of numpy/pandas.

v1.2.0 (2019/5/21)

This result has been superseded by 1.2.1. See release notes for details.

v1.1.0 (2018/6/26)

See v1.1.0 for information regarding enhancements.

v1.0.0 (2017/5/25)

See v1.0.0 for information regarding enhancements.

v0.8.0 (2016/8/21)

See v0.8.0 for information regarding enhancements.

v0.7.2 (2015/4/25)

See v0.7.2 for information regarding enhancements.

Version 0.6.1 has been released (2013/6)

Version 0.6 improves BDF reading. The reader is more robust and also requires proper BDF field formatting (e.g. an integer field can't be a float). Additionally, cards also have a comment() method.

Marcin Gąsiorek participated in the latest pyNastran under the European Space Agency's (ESA) "Summer of Code In Space" SOCIS program. The program provides a stipend to students to work on open-source projects. He did a great job of simplifying code and creating nicer documentation.