The community continuation of OpenRadioss
OpenCourant is an open-source finite element solver for crash, impact, and highly nonlinear dynamic simulation, carrying forward the OpenRadioss code base under the GNU AGPL, in the open, where it belongs.
What happened to OpenRadioss?
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-driven development on the open-source version of the Radioss finite element solver, originally published by Altair in 2022.
The code, however, 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, so that this work remains open, permanently, for everyone.
Why “Courant”?
The name honors Richard Courant and the Courant–Friedrichs–Lewy (CFL) condition, the stability criterion at the heart of every explicit time-integration solver, including this one. It’s a nod to the numerical foundations this community builds on.
Where things stand
The solver builds, runs, and ships. Continuous integration has been rebuilt on OpenCourant’s own infrastructure, replacing the vendor-internal pipeline it inherited; the regression suite gates every release; and stable packages for Linux x86-64, Linux arm64 and Windows are published automatically, alongside multi-arch container images on Docker Hub and GHCR. Get the latest build →
The full commit history came across intact, so the work of everyone who contributed to OpenRadioss is preserved and attributed. A few proprietary build-time pieces still need open replacements, and that work is tracked in the open.
We’re looking for the OpenRadioss community
The code is safe and the builds are flowing. What this project still needs is its people. If you were a user, contributor, researcher, or maintainer of OpenRadioss, or you’re just interested in open-source crash and impact simulation, we want to hear from you.
- Code The solver lives at github.com/OpenCourant/OpenCourant. Issues and pull requests are open.
- Forum Ask questions, propose changes, and follow release threads in GitHub Discussions.
- Chat For realtime conversation, join the #opencourant channel on the Rocky Linux Mattermost.
- Email Email the project directly at hello@opencourant.org.
Former OpenRadioss maintainers and community leaders: please get in touch. We want governance and direction for this project to be set by the people who built it.
News
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All three platforms now ship
Linux x86-64, Linux arm64 and Windows packages are all published from the same pipeline, each gated on the same regression suite. ARM was unblocked by a community donation of a lost reader package.
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The first OpenCourant builds are here
Stable Linux packages are now published automatically from OpenCourant’s own continuous integration. Here’s what it took to rebuild the delivery pipeline, what the community already fixed, and what is still missing.
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Announcing OpenCourant, the community continuation of OpenRadioss
OpenRadioss has been discontinued and its repository deleted. The code lives on: OpenCourant continues from the last available open-source code base, and we’re calling on the OpenRadioss community to regroup.
