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Licensing

Vulcan software licensing and open source components

How Vulcan is licensed

Vulcan is developed by Home Energy Foundry Limited and licensed in two ways: an open-source core, and a proprietary hosted platform built around it.

Vulcan Community (open source)

The core Vulcan editor (2D / 3D geometry authoring, CSV-to-HEM conversion and Future Homes Standard preflight) is developed in the open as vulcan-community. It is licensed AGPL-3.0-only, supplemented by the Vulcan Origin Terms, with separately identified licences for interoperability code, data and upstream components. The vulcan-csv-codec interoperability crate is Apache-2.0, so any application can read and write Vulcan-compatible files without copyleft obligations, and the documentation is CC BY 4.0. hem-htc-harness (the H3 heat-transfer-coefficient harness) is licensed the same way. See Open Source for how the open projects relate to the official product.

The hosted Vulcan platform (proprietary)

The hosted Vulcan platform and Pro functionality (accounts, building regulations functionality, AI functionality, project organisation and bulk editing, and cloud backups) are proprietary software of Home Energy Foundry Limited, licensed, not sold. The full proprietary licence text is available at LICENSE.txt. Home Energy Foundry Limited owns the Vulcan Community code and dual-licenses it, so official Vulcan builds ship it under the proprietary licence alongside these closed components.

Commercial licensing

Home Energy Foundry offers Vulcan Community under separate commercial terms for closed-source use, including white-label terms without visible attribution. For commercial licensing or any other licensing inquiry, contact info@usevulcan.app.

Redistributed Components

Vulcan redistributes certain open-source and third-party components. This section provides details about each component, its license, and how to access corresponding source code.

Overview

ComponentPurposeLicenseDetails
IfcOpenShellIFC file import parsingLGPLv3 / GPLv3View details
HEM EngineHome Energy Model calculation engineMITView details
Pyodide RuntimePython runtime for browserApache 2.0View details
Bundled DependenciesRust crates and JavaScript packagesVarious (mostly MIT/Apache-2.0)View details
H3 Demo BundleBrowser H3 sandbox on /h3AGPL-3.0-onlyView details

IfcOpenShell (LGPLv3)

Vulcan uses IfcOpenShell for IFC (Industry Foundation Classes) file import functionality. IfcOpenShell is licensed under the GNU Lesser General Public License v3.0 (LGPLv3) and GNU General Public License v3.0 (GPLv3).

User Replacement

In compliance with LGPLv3 requirements, users can replace the IfcOpenShell library used by Vulcan. This can be done through the Advanced Settings in the IFC import modal, where you can specify a custom wheel URL.

Shipped Versions

VersionCommitFilenameDefaultLicense
0.8.4283ad7difcopenshell-0.8.4+283ad7d-cp313-cp313-pyodide_202...LGPLv3, GPLv3
0.8.334a1bc6ifcopenshell-0.8.3+34a1bc6-cp313-cp313-emscripten_...✓LGPLv3, GPLv3

Corresponding Source

For each shipped version, corresponding source code is available:

  • 0.8.4 (commit 283ad7d): GitHub
  • 0.8.3 (commit 34a1bc6): GitHub

Upstream repository: IfcOpenShell on GitHub

License texts: Each wheel file contains embedded license texts:

  • COPYING.LESSER (GNU LGPL v3)
  • COPYING (GNU GPL v3)

HEM Engine (MIT)

Vulcan includes the Home Energy Model (HEM) engine, which performs energy performance calculations for buildings. The HEM engine is licensed under the MIT License.

Source Code

Redistributed Schemas

Vulcan redistributes JSON schema files derived from the HEM engine:

  • input_core_allowing_fhs.schema.json - Available at /hem_engine/schemas/input_core_allowing_fhs.schema.json
  • input_fhs.schema.json - Available at /hem_engine/schemas/input_fhs.schema.json

These schemas are derived from the MIT-licensed HEM engine source code.

Pyodide Runtime (Apache 2.0)

Vulcan uses Pyodide to run Python code in the browser, enabling IFC file parsing functionality. Pyodide is licensed under the Apache License 2.0.

Version

Redistributed Files

Pyodide runtime files are available at /pyodide/:

  • pyodide.asm.js
  • pyodide.asm.wasm
  • python_stdlib.zip (Python standard library, PSF License)
  • pyodide-lock.json
  • packaging-22.1-py3-none-any.whl

Bundled Dependencies

Vulcan bundles additional dependencies that are compiled or packaged with the application:

Rust Crates (Compiled into WASM)

The Vulcan WASM binary (wasm_wrapper_bg.wasm) includes Rust crates compiled from source. Major dependencies include:

  • HEM Engine - MIT (see HEM Engine section above)
  • hem-batch-core - Proprietary (developed by Home Energy Foundry Limited)
  • wasm-bindgen, js-sys, web-sys - Apache-2.0 / MIT
  • serde, serde_json - MIT / Apache-2.0
  • chrono - MIT / Apache-2.0
  • rayon - Apache-2.0 / MIT
  • jsonschema - Apache-2.0
  • Additional transitive dependencies (mostly MIT/Apache-2.0)

Note: These crates are compiled into the WASM binary and are not separately redistributed. Most dependencies are licensed under MIT or Apache-2.0.

JavaScript Packages (Bundled in Web App)

The Vulcan web application bundles JavaScript dependencies. Major packages include:

  • React, React DOM - MIT
  • Material-UI (@mui/material) - MIT
  • Konva, react-konva - BSD-2-Clause
  • CodeMirror (@codemirror/*) - MIT
  • JSON Forms (@jsonforms/*) - MIT
  • TanStack (@tanstack/react-query, @tanstack/react-table) - MIT
  • Supabase Client (@supabase/supabase-js) - MIT
  • Additional dependencies

Note: These packages are bundled into JavaScript chunks. Most dependencies are licensed under MIT or Apache-2.0.

H3 Demo Bundle (AGPL 3.0)

The interactive H3 sandbox on /h3 runs an open-source bundle served from this site under /h3-demo/. The bundle is built from hem-htc-harness, published by Home Energy Foundry Limited under AGPL-3.0-only.

Corresponding Source

The bundle manifest at /h3-demo/h3-demo.json records the exact commit the bundle was built from. Corresponding source for that commit is available from the hem-htc-harness repository and its releases.

Third-Party Notices

IfcOpenShell 0.8.4 - LGPLv3 / GPLv3
IfcOpenShell 0.8.3 (default) - LGPLv3 / GPLv3

Questions?

For licensing inquiries or to request source code for any redistributed component, please contact: info@usevulcan.app