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:
- 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?