An open-source explicit finite element solver for simulating crashes, impacts, explosions, and other highly nonlinear dynamic events. Free software under the GNU AGPL v3.
Website · Downloads · Forum · Chat · Email
On October 1, 2026, Siemens discontinued the OpenRadioss project. The website was retired and the GitHub repository was removed without an archive, taking with it four years of community work on the open-source version of the Radioss finite element solver.
The code was released under the GNU AGPL v3, and free software doesn't disappear just because a repository does. OpenCourant continues from the last available open-source code base, with the full commit history intact, so the work of everyone who contributed to OpenRadioss is preserved and attributed.
Pre-built packages are published automatically from continuous integration, gated on the regression suite:
That page always reflects the platforms currently being produced. To build from source, start with HOWTO.md.
| Forum | GitHub Discussions, for questions, proposals, release threads and announcements. Start here. |
| Chat | Realtime, in #opencourant on the Rocky Linux Mattermost. |
| Issues | Bug reports and tracked work, in the relevant repository. |
| [email protected], for anything that doesn't fit the above. |
| OpenCourant | The solver: Starter, Engine, and the input reader. |
| Tools | Converters, the launcher GUI, and the SDK. |
| extlib | External build libraries, with recovery provenance documented. |
| ci-images | CI container images, published to ghcr.io/opencourant. |
| opencourant.org | The website. |
| branding | Logos and marks, CC BY-SA 4.0. |
- The recovery succeeded. The community's archived files restored the complete final upstream library set, now shipping in every build on every platform — read how it ended →. What remains is making it unnecessary: see the open reader below.
- The open reader. The AGPL-licensed input reader already in the repository is a handful of functions short of replacing the proprietary one on every platform, ARM included. It is the durable fix for an entire class of problem.
- Testing on real models. The regression suite gates every release, but it cannot cover the range of decks people actually run. Try your own models and tell us what breaks.
- Former OpenRadioss maintainers and community leaders, please get in touch. We want this project's technical direction and governance to be set by the people who built it.
Radioss is a trademark of its respective owner. OpenCourant is an independent community project and is not affiliated with or endorsed by Siemens or Altair.
