OpSim is released under the GNU General Public License (GPL, or “free software”).
This license grants people a number of freedoms:
The GPL strictly aims at protecting these freedoms, requiring everyone to share their modifications when they also share the software in public. That aspect is commonly referred to as Copyleft.
What you create with OpSim is your sole property. All your work – models, simulations or scripts – including the .opsim files and other data files OpSim can write, is free for you to use as you like.
That means that OpSim can be used commercially by engineers, by engineering companies to make commercial simulations, by scientists for research, and by students in educational institutions.
OpSim’s GNU GPL license guarantees you this freedom. Nobody is ever permitted to take it away, in contrast to trial or “educational” versions of commercial software that will forbid your work in commercial situations