I'm using Qt Open source so I have my software under GPL-3 license. I would like the engine to be free for users that are not using their output games for commercial use. For commercial use, I would like to ask for some fees. I know that as long as a user pay fees for the software license it can be redistribute without charges and that's the wrong point. What about outputs?

What the output contains:

  • Javascript interpreted source code under GPL-3 license
  • Assets (does GPL license allows me to produce output containing commercial assets?)
  • Dynamically linked Qt libraries
  • Executable generated by Qt

I was thinking about asking users for autorization for using assets under that license: https://creativecommons.org/licenses/by-nc/4.0/. However, I guess that Iloose all the rights to ask for fees if they remove the assets and use their own assets. Is there any possible trick to do my purpose?

  • 1
    Possible duplicate of Non-commercial licensing recommendation
    – MadHatter
    Commented Mar 29, 2019 at 9:59
  • Thanks for the link. I'm not sure about having to put my JavaScript source code under GPL-3 license since it can work on any web browser without any change. Qt only makes it available on desktop application. Can I use a dual license to use CC-Non-Commercial for my creations (assets + JavaScript code)?
    – Nat
    Commented Mar 29, 2019 at 10:18
  • That seems to me to be a completely different question; it would be better to ask it as one.
    – MadHatter
    Commented Mar 29, 2019 at 10:19
  • 1
    What makes this interesting in my mind is the fact that you can get a non-free license for Qt for use in closed source/commercial work. But.. If I use your Qt-gpl based game to go non-free I'd need a non-free Qt license as well - depending on how your code is structured, it may not be GPL-able in that case. Alternatively, you could hire lawyers and figure out how to duplicate Qt's dual license setup.
    – ivanivan
    Commented Mar 31, 2019 at 2:40
  • 1
    In fact, I didn't see that a large set of Qt libraries were also under LGPL-3 license. If I understand it well, this makes me able to have my output under another license even if it's using Qt libraries. I just have to use dynamic linking.
    – Nat
    Commented Apr 1, 2019 at 7:24


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