I had Claude code up an OMI Physics package using Numpy. It's up on pypi as omi_physics. This follows the OMI extensions to glTF pretty closely to create an engine with the common features you need. It's not trying to be real-world physics, it's just a game engine style simulation.

The core is GL-free, with a few GPGPU kernels to optimise certain bits over 10,000 objects, but in testing any more than about 300 objects brings the rendering below 60fps in OpenGLContext. To get around that we'd need to move the whole physics process into the GPU with a very different solver, and I don't currently need that.

License is MIT, though most of the code is written by Claude, so arguably it's non-copyright.