The community continuation of OpenRadioss

What happened to OpenRadioss?

On October 1, 2026, Siemens discontinued the OpenRadioss project. The website was retired and the GitHub repository — home to four years of community-driven development on the open-source version of the Radioss finite element solver, originally published by Altair in 2022 — was removed without an archive.

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 Linux and Windows packages are published automatically. Get the latest build →

The full commit history came across intact, so the work of everyone who contributed to OpenRadioss is preserved and attributed. Linux arm64 builds run natively in an experimental pipeline and aren’t packaged here yet, and a few proprietary build-time pieces still need open replacements. All of it 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 simply 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.

This is not an abstraction: when we asked whether anyone had archived a build dependency that vanished with the upstream repository, someone did. That contribution improved every Linux build published since.

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.