Licences and third-party notices
On this page
This page lists the licence of each Tractrix product and every third-party component and dataset they use, with how each is used and whether it is distributed. It mirrors THIRD_PARTY_NOTICES.md in the repository, which is shipped with each distribution. The licence texts in the repository and in each package govern.
Versions are the minimums declared in the manifests, with the versions tested at the time of writing in brackets. Distributed means the component is included in something REAT Global ships (a binary, installer, bundle, plugin package or container image); build / test only components are not shipped. This list must be re-checked for each release.
1. Licences of the Tractrix products
| Product | Source | Licence |
|---|---|---|
OpenAirside engine and tractrix-engine | openairside/core, engine/ | GPL-2.0-or-later |
| Tractrix for QGIS | openairside/ | GPL-2.0-or-later (the licence required for QGIS plugins) |
| Tractrix for AutoCAD, Tractrix for Revit | cad/ | GPL-2.0-or-later |
| Tractrix Cloud (source code) | platform/ | GPL-2.0-or-later. The hosted service is provided under the Cloud Terms, which do not restrict your rights in the source |
| Brand assets | brand/ | © REAT Global; use governed by the trademark policy |
Copyright © 2026 REAT Global and the OpenAirside contributors. Full text: Downloads (account required) and gnu.org. How the licence applies to the desktop software, the warranty disclaimer and the source offer are set out in the desktop software licence.
2. Source code offer
3. Data
| Data | Used in | Licence / status | Source |
|---|---|---|---|
| FAA Aircraft Characteristics Database (ACD) | openairside/data/aircraft.json (388 types); all products; distributed | Public domain (work of the US Government, 17 U.S.C. § 105). Use does not imply FAA endorsement. Some geometry needed by the model is estimated and flagged | Federal Aviation Administration |
| Manufacturer steering limits and validation radii | tools/aircraft_overrides.json, merged into the library; distributed | Individual numeric facts read from public airport-planning documents; each entry cites its source. No document, drawing or data file is reproduced | The Boeing Company, Airbus S.A.S. (documents); values compiled by the OpenAirside contributors |
| Vehicle / GSE library | openairside/data/vehicles.json; distributed | GPL-2.0-or-later; mostly generic class dimensions, a few records cite public product listings | OpenAirside contributors |
| ICAO, FAA and EASA standards | Clearances, margins and jet-blast calibration in openairside/core/ | Referenced, not reproduced: only individual values are used, with citations (ICAO Annex 14 Vol. I, ICAO Doc 9157 Part 2, FAA AC 150/5300-13B, EASA CS-ADR-DSN). The publications themselves must be obtained from their publishers | ICAO, FAA, EASA |
No vendor library, data file or software of any commercial swept-path tool was used or reverse-engineered.
4. Fonts
| Component | Used in | Licence | Copyright |
|---|---|---|---|
| IBM Plex Sans, Serif and Mono (Latin-1 subsets, WOFF2) | Website and Cloud web app (distributed, self-hosted — no requests to font services); referenced by name in HTML reports | SIL Open Font License 1.1 | Copyright © 2017 IBM Corp., with Reserved Font Name “Plex” |
| Segoe UI | CAD add-in dialogs (by name) | Supplied by Windows; not distributed | Microsoft Corporation |
The IBM Plex fonts are licensed under the SIL Open Font License, Version 1.1, available with FAQ at openfontlicense.org. The subsets are modified versions and are distributed as separate font files; the OFL permits bundling them with software under any licence.
5. OpenAirside engine and Tractrix for QGIS
| Component | Use | Licence | Copyright |
|---|---|---|---|
| Python | Runtime; embedded in tractrix-engine.exe (distributed) | PSF-2.0 | Python Software Foundation |
| Shapely ≥ 2.0 [2.1.2] | Geometry; embedded in tractrix-engine.exe and the Cloud image (distributed) | BSD-3-Clause | Sean C. Gillies, Casper van der Wel and Shapely contributors |
| GEOS (inside Shapely wheels) | Geometry kernel; distributed with Shapely | LGPL-2.1 | GEOS contributors |
| NumPy ≥ 1.21 [2.4.6] | Arrays; embedded in tractrix-engine.exe and the Cloud image (distributed) | BSD-3-Clause; wheels also bundle OpenBLAS and LAPACK (BSD-3-Clause) and the GCC runtime (GPL-3.0-or-later with the GCC Runtime Library Exception) | NumPy Developers; OpenBLAS / LAPACK authors; Free Software Foundation |
| PyInstaller ≥ 6.0 [6.22.3] | Builds tractrix-engine.exe; its bootloader is embedded (distributed) | GPL-2.0-or-later with the PyInstaller bootloader exception; some runtime hooks Apache-2.0 | PyInstaller Development Team |
| jsonschema ≥ 4.18 [4.26.0] | Protocol schema tests only | MIT | Julian Berman |
| QGIS, Qt, PyQt | Host application of the plugin; not distributed | GPL-2.0-or-later (QGIS); LGPL-3.0 / GPL (Qt); GPL-3.0 (PyQt) | QGIS.org; The Qt Company; Riverbank Computing |
6. Tractrix for AutoCAD and Revit
| Component | Use | Licence | Copyright |
|---|---|---|---|
| .NET 8 runtime, WPF, WinForms, System.Text.Json | Runtime supplied by AutoCAD / Revit; not distributed | MIT | .NET Foundation and contributors / Microsoft Corporation |
| System.Security.Cryptography.ProtectedData 8.0.0 | DPAPI encryption of the stored API token | MIT | .NET Foundation and contributors |
AutoCAD.NET 25.0.1 NuGet (with AutoCAD.NET.Core, AutoCAD.NET.Model) | Reference assemblies at compile time only; not distributed. AutoCAD supplies the real assemblies at run time | Autodesk licence terms (proprietary) | Autodesk, Inc. |
Nice3point.Revit.Api.RevitAPI / .RevitAPIUI 2025.4.60 NuGet | Reference assemblies at compile time only; not distributed. Revit supplies the API assemblies at run time | Package: MIT; the Revit API assemblies: Autodesk licence terms | Nice3point; Autodesk, Inc. |
| WiX Toolset v4 (with WixToolset.UI.wixext) | Builds the MSI installer; its custom actions and UI are embedded in the MSI (distributed) | MS-RL | .NET Foundation and contributors |
| xUnit 2.9.2, xunit.runner.visualstudio 2.8.2 | Tests only | Apache-2.0 | .NET Foundation |
| Microsoft.NET.Test.Sdk 17.11.1 | Tests only | MIT | Microsoft Corporation |
OpenAirside engine (tractrix-engine.exe) | Bundled in Contents/engine (distributed) | GPL-2.0-or-later, plus the components in section 5 | REAT Global and contributors |
7. Tractrix Cloud
| Component | Licence | Copyright |
|---|---|---|
| FastAPI ≥ 0.110 [0.142] | MIT | Sebastián Ramírez |
| Starlette ≥ 0.37 | BSD-3-Clause | Encode OSS Ltd. |
| Uvicorn[standard] ≥ 0.29 [0.54] | BSD-3-Clause; extras httptools (MIT), uvloop (MIT / Apache-2.0), websockets (BSD-3-Clause), watchfiles (MIT), python-dotenv (BSD-3-Clause), PyYAML (MIT) | Encode OSS Ltd. and respective authors |
| SQLAlchemy ≥ 2.0 [2.1] | MIT | The SQLAlchemy authors and contributors |
| Alembic ≥ 1.13 [1.20] (with Mako, MarkupSafe) | MIT (Mako: MIT; MarkupSafe: BSD-3-Clause) | The Alembic authors |
| Pydantic ≥ 2.6 [2.13], pydantic-core, pydantic-settings ≥ 2.2 [2.15] | MIT | Samuel Colvin and contributors |
| email-validator ≥ 2.1 (with dnspython, idna) | The Unlicense (dnspython: ISC; idna: BSD-3-Clause) | Joshua Tauberer |
| argon2-cffi ≥ 23.1 | MIT; bundles the Argon2 reference implementation (CC0-1.0 / Apache-2.0) | Hynek Schlawack and contributors |
| PyJWT ≥ 2.7 | MIT | José Padilla |
| python-multipart ≥ 0.0.9 | Apache-2.0 | Andrew Dunham, Marcelo Trylesinski |
| ezdxf ≥ 1.2 | MIT | Manfred Moitzi |
| Shapely, NumPy | See section 5 | |
| psycopg[binary] ≥ 3.1 | LGPL-3.0-only; the binary wheel bundles libpq (PostgreSQL Licence) and OpenSSL (Apache-2.0) | Daniele Varrazzo; PostgreSQL Global Development Group; OpenSSL Project |
| anyio, h11, click, typing-extensions, cffi, greenlet (transitive) | MIT / BSD-3-Clause / PSF-2.0 | Their respective authors |
| Python 3.11 slim base image | PSF-2.0 and the Debian packages' licences | Python Software Foundation; Debian |
| PostgreSQL 16 (docker-compose default, not in the image) | PostgreSQL Licence | PostgreSQL Global Development Group |
| pytest, httpx (tests only) | MIT, BSD-3-Clause | Holger Krekel and others; Encode OSS Ltd. |
The Cloud web app and this website use no third-party JavaScript or CSS frameworks and make no requests to third-party services.
8. Licence compatibility
- Our code is GPL-2.0-or-later, so combinations may be distributed under GPL-3.0 where a component requires it.
- Permissive licences (MIT, BSD-3-Clause, ISC, PSF-2.0, the Unlicense, CC0, the PostgreSQL Licence) are compatible with GPL-2.0 and GPL-3.0; their notices are preserved here and in the packages.
- Apache-2.0 components (python-multipart, OpenSSL 3, some PyInstaller hooks) are compatible with GPL-3.0 but not GPL-2.0-only. Because our licence is “or later”, the affected combinations are distributable under GPL-3.0. Running Tractrix Cloud as a hosted service is not a distribution under the GPL.
- LGPL components (GEOS, psycopg) are used as separate, dynamically loaded libraries and remain replaceable.
- GPL with exceptions (PyInstaller bootloader exception, GCC Runtime Library Exception) expressly permit distribution of the resulting executables.
- MS-RL (WiX runtime parts in the MSI) is a file-level copyleft that applies only to WiX's own files.
9. Trademarks
Tractrix™ and the Tractrix logo are trademarks of REAT Global. AutoCAD and Revit are registered trademarks of Autodesk, Inc.; QGIS is a trademark of QGIS.org; Airbus and Boeing are trademarks of their respective owners. They are used to identify products and data sources and imply no affiliation or endorsement. See the trademark policy.