Desktop software licence and terms

Draft — to be reviewed by counsel

This is a working draft prepared for review by qualified counsel. It is not legal advice and is not yet binding. Items in [SQUARE BRACKETS] are placeholders to be completed by REAT Global; notes marked “Counsel:” are decisions for review. See the placeholder register.

Version 1.0-draftLast updated [LAST UPDATED DATE]Effective [EFFECTIVE DATE]Draft prepared 30 September 2026

On this page

This page sets out the licence and notices for the Tractrix desktop software. In short: it is free software under the GNU General Public License, version 2 or later. You do not have to accept anything to run it, and nothing here takes away any right the GPL gives you.

1. What this covers

This page applies to the following software published by REAT Global (the “Software”), in source and binary form, including installers, the Autodesk bundle and the QGIS plugin package:

Tractrix for QGIS (the openairside QGIS plugin);
Tractrix for AutoCAD and Tractrix for Revit (the CAD add-ins);
the OpenAirside engine (tractrix_engine Python package and the OpenAirside core) and the single-file tractrix-engine executable bundled with the CAD add-ins.

Tractrix Cloud, the hosted service, is governed by the Cloud Terms; see section 7.

2. Licence: GPL-2.0-or-later

The Software is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version (SPDX identifier GPL-2.0-or-later).

The full licence text is in the Downloads (account required) file of the repository, in LICENSE.txt in the Autodesk bundle, in the plugin package, and at gnu.org.
In summary: you may run the Software for any purpose, including commercial projects; study and modify it; and redistribute copies, modified or not, provided you pass on the same freedoms, include the licence and copyright notices, and make the corresponding source code available. This summary is for convenience; the licence text governs.
As section 5 of GPL v2 explains, you are not required to accept the licence in order to run the Software. Clicking “I agree” in an installer only confirms that you have seen these notices; it does not add any term to the GPL.
Aircraft data in the library derives from the FAA Aircraft Characteristics Database, which is in the public domain; see Licences.

3. Source code and written offer

The complete corresponding source code of every release — including the build scripts used to produce the binaries (for example engine/tractrix-engine.spec, engine/build_binary.py and the cad/packaging scripts) — is published in the Downloads (account required), tagged for each release, and linked from the same download page as the binaries.

Written offer. In addition, for at least three years from the date you received a binary from us, and for as long as we offer spare parts or support for that version, REAT Global will give any third party, on request, a complete machine-readable copy of the corresponding source code, on a medium customarily used for software interchange, for a charge no more than our cost of physically performing the distribution. Write to [LEGAL NOTICES EMAIL] or [REGISTERED ADDRESS], stating the product and version.

Source code of third-party components that are distributed with the Software under a licence requiring it (such as the LGPL-licensed GEOS library inside Shapely) is available from us on the same terms, and from their upstream projects listed on the licences page.

4. No warranty

The following is section 11 of GPL version 2 (section 15 of version 3 is equivalent):

BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

5. Limitation of liability

The following is section 12 of GPL version 2 (section 16 of version 3 is equivalent):

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Where the law of your country does not allow warranties or liability to be excluded or limited in this way (for example liability for death or personal injury caused by negligence, or for fraud, or mandatory consumer rights), those exclusions and limitations apply only to the extent the law permits.

6. Additional notices (no additional restrictions)

The notices in this section are information. They are not further restrictions on the rights the GPL gives you, and if anything in them conflicts with the GPL, the GPL prevails (GPL v2 section 6).

Engineering use. Results are planning aids, not certified design results. Verify them against the manufacturers' airport planning documents and the applicable standards before relying on them, and do not use the Software for operational purposes. See the Engineering disclaimer. The reports produced by the Software include a notice to this effect.
Export control and sanctions. Export-control and sanctions laws may apply to you independently of any licence when you export or re-export software or technical data. The Software's export classification is [EXPORT CLASSIFICATION]. As published free and open-source software it may be outside the scope of some controls; you are responsible for your own compliance.
Trademarks. The GPL does not grant rights in the Tractrix names or logos. Modified versions must be renamed as described in the trademark policy.
Contributions. Contributions to the project are accepted under the terms in CONTRIBUTING.md in the repository, and licensed under GPL-2.0-or-later.

7. Cloud mode of the CAD add-ins

By default the CAD add-ins run the local engine and make no network connections. If you choose the cloud engine in the add-in settings and enter a Tractrix Cloud address and API token, the add-in asks for your consent and then sends each simulation request (path, pavement and obstacle geometry, aircraft or vehicle and parameters) to that server over HTTPS. Your use of Tractrix Cloud in this way is governed by the Cloud Terms, the Acceptable Use Policy, the DPA (for your organisation) and the Privacy notice. The GPL continues to govern the add-in software itself. You can withdraw consent and return to the local engine at any time in the add-in settings.

8. Privacy

The Software contains no telemetry, analytics or automatic update checks, and does not send your drawings, results or usage data to REAT Global. The CAD add-ins keep their settings in %AppData%\Tractrix\settings.json; an API token, if you enter one, is encrypted with Windows DPAPI for your Windows user and is removed from messages and reports. See the Privacy notice.

9. Host applications

Tractrix for AutoCAD and Tractrix for Revit require a licensed copy of Autodesk AutoCAD or Autodesk Revit, obtained from Autodesk under Autodesk's own terms. The add-ins use Autodesk's public plug-in interfaces; Autodesk's API assemblies are used only as reference assemblies at build time and are not distributed with the Software. AutoCAD and Revit are registered trademarks of Autodesk, Inc. Tractrix is not affiliated with, sponsored by or endorsed by Autodesk.
If you obtain the add-ins through the Autodesk App Store, Autodesk's store terms also govern that transaction; they do not restrict the rights the GPL gives you in the Software.
Tractrix for QGIS requires QGIS, obtained from QGIS.org under the GPL. QGIS is a trademark of QGIS.org. Tractrix for QGIS is not affiliated with or endorsed by QGIS.org or OSGeo.

10. Third-party components

The Software includes or depends on third-party components under their own licences, including Python, Shapely (with GEOS), NumPy and the PyInstaller bootloader in the tractrix-engine executable, and the IBM Plex fonts. The full list, with licences and copyright holders, is on the licences page and in THIRD_PARTY_NOTICES in each distribution.

11. Support and updates

Community support is available through GitHub Discussions and issues. We are not obliged to provide support, maintenance or updates for the Software, but we publish security fixes for supported versions as described on the security page. Paid support may be agreed separately; such an agreement does not change the licence of the Software.

12. Contact

Licensing questions: [LEGAL NOTICES EMAIL] · [REGISTERED ADDRESS]. Licence compliance issues can also be reported on GitHub with the label licensing.