The best OpenSim alternatives
The rest of Best Physics Simulation Software, in this site's order.
SimFlow suits engineers who need a local CFD workflow and CAD import and results export options.
OpenFOAM is suited to science and engineering companies, consultancies, and universities that need fluid dynamics simulation tools.
It is aimed at engineers, scientists, technical enterprises, research laboratories, and universities.
It suits people working with circuit netlists who need analog, digital, or mixed-signal simulation.
It suits learners who want to focus on physics concepts before solving problems by hand.
The Physics Classroom describes the collection as primarily for beginning physics students and their teachers.
FeenoX is aimed at advanced users, including engineers, Unix hackers, and academics who work with engineering problems on GNU/Linux.
Step suits Linux users learning or exploring physics through editable simulations.
MPTRAC suits atmospheric researchers studying transport, dispersion, or chemistry who can work with meteorological input data.
FEST-3D suits users working on aerodynamic flow simulations who can build and configure scientific software.