updated license to account for GPL3 models

LICENSE

@@ -0,0 +1,44 @@
+Creative Commons Attribution 4.0 International (CC BY 4.0)
+
+Copyright (c) 2025 Sylvain Hellin, Technical University of Munich
+
+SCOPE: This license applies to the IFC-Bench dataset — specifically the
+question-answer pairs, documentation, model cards, and all original content
+created for this repository.
+
+IFC MODEL FILES: The IFC model files included under projects/ retain their
+original licenses as specified in each project's license.txt file. Most models
+are licensed under CC BY 4.0 or MIT, but the following models are licensed
+under the GNU General Public License v3.0 (GPLv3):
+
+  - projects/4351/          (GPLv3, BIMserver.org)
+  - projects/ettenheim_gis/ (GPLv3, BIMserver.org)
+  - projects/hitos/         (GPLv3, BIMserver.org)
+  - projects/samuel_macalister_sample_house/ (GPLv3, BIMserver.org)
+
+Users must comply with each model's individual license terms when
+redistributing or creating derivative works that include those model files.
+See each project's license.txt for details.
+
+--- CC BY 4.0 License Text ---
+
+You are free to:
+
+  Share — copy and redistribute the material in any medium or format for any
+  purpose, even commercially.
+
+  Adapt — remix, transform, and build upon the material for any purpose, even
+  commercially.
+
+Under the following terms:
+
+  Attribution — You must give appropriate credit, provide a link to the
+  license, and indicate if changes were made. You may do so in any reasonable
+  manner, but not in any way that suggests the licensor endorses you or your
+  use.
+
+  No additional restrictions — You may not apply legal terms or technological
+  measures that legally restrict others from doing anything the license
+  permits.
+
+Full license text: https://creativecommons.org/licenses/by/4.0/legalcode

README.md

@@ -95,7 +95,7 @@ ifc-bench/
 | Project | Disciplines | License | Usage | Source |
 |---------|-------------|---------|-------|--------|
 | `4351` | Architecture | GNU GPL v3 | unspecified | [BIMserver TestFiles](https://github.com/opensourceBIM/TestFiles) |
-| `ac20` | Architecture | unrestricted | office | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
+| `ac20` | Architecture | CC BY 4.0 | office | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
 | `city_house_munich` | Architecture | CC BY 4.0 | living | N/A |
 | `dental_clinic` | Architecture, Structural, MEP | CC BY 4.0 | healthcare | [buildingSMART](https://github.com/buildingsmart-community/Community-Sample-Test-Files) |
 | `digital_hub` | Architecture, Heating, Plumbing, Ventilation | MIT | office | [RWTH E3D](https://github.com/RWTH-E3D/DigitalHub) |
@@ -107,13 +107,13 @@ ifc-bench/
 | `fantasy_office_building_2` | Architecture | MIT | office | TUM BIM Fundamentals SS2025 |
 | `fantasy_office_building_3` | Architecture | MIT | office | TUM BIM Fundamentals SS2025 |
 | `fantasy_residential_building_1` | Architecture | MIT | living | TUM BIM Fundamentals SS2025 |
-| `fzk_house` | Architecture | unrestricted | living | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
+| `fzk_house` | Architecture | CC BY 4.0 | living | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
 | `hitos` | Architecture | GNU GPL v3 | office | [BIMserver TestFiles](https://github.com/opensourceBIM/TestFiles) |
 | `molio` | Architecture | CC BY 4.0 | office | [buildingSMART](https://github.com/buildingsmart-community/Community-Sample-Test-Files) |
 | `samuel_macalister_sample_house` | Architecture, MEP | GNU GPL v3 | living | [BIMserver TestFiles](https://github.com/opensourceBIM/TestFiles) |
 | `schependomlaan` | Architecture | CC BY 4.0 | living | [openBIM Archive](https://github.com/openBIMstandards/Archive-DataSetSchependomlaan) |
 | `sixty5` | Architecture, Electrical, Facade, Kitchen, Plumbing, Structural, Ventilation | CC BY 4.0 | living | [buildingSMART](https://github.com/buildingsmart-community/Community-Sample-Test-Files) |
-| `smiley_west` | Architecture | unrestricted | living | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
+| `smiley_west` | Architecture | CC BY 4.0 | living | [KIT IFC Examples](https://www.ifcwiki.org/index.php?title=KIT_IFC_Examples) |
 | `wbdg_office` | Architecture, MEP, Structural | CC BY 4.0 | office | [WBDG](https://www.wbdg.org/bim/cobie/common-bim-files) |
 
 <table>
@@ -242,8 +242,11 @@ Please see our [Contribution Guidelines](docs/CONTRIBUTING.md) for details.
 
 ## License
 
-- **Dataset**: Licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/)
-- **Models**: Inherit their original licenses (see individual project folders)
+- **Dataset** (question-answer pairs, documentation, model cards, and all original content): Licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
+- **IFC models**: Each model retains its original license as specified in its project's `license.txt`. The majority of models are licensed under CC BY 4.0 or MIT. However, the following models are licensed under **GNU GPLv3** and are subject to its copyleft terms:
+  - `4351`, `ettenheim_gis`, `hitos`, `samuel_macalister_sample_house` (source: [BIMserver TestFiles](https://github.com/opensourceBIM/TestFiles))
+
+  Users who redistribute or create derivative works that include these GPLv3 model files must comply with the GPLv3 license terms for those files. See each project's `license.txt` for details.
 
 ## Citation
 

docs/CONTRIBUTING.md

@@ -12,7 +12,7 @@ If you find a bug, an error in the dataset, or have a suggestion, please open an
 
 We are always looking for new IFC models to expand the dataset. When contributing a new model, please ensure: 
 
--   **Licensing**: The model must be available under a permissive open-source license (e.g., CC BY 4.0, MIT).
+-   **Licensing**: The model must be available under a permissive open-source license (e.g., CC BY 4.0, MIT). Models with copyleft licenses (e.g., GPLv3) may be accepted but will be clearly flagged in the dataset documentation, as they impose additional redistribution requirements on downstream users.
 -   **Format**: The model must be in the IFC format.
 -   **Documentation**: Provide a brief description of the model, including its purpose, size, and complexity.
 -   **Organization**: Place the model files in a new folder under the `projects/` directory. Include a `license.txt` file and a `model_card.md` (Markdown format) with the model's metadata.