Hi, I'm new to this board. I've read some information about this great project, but I'm unsure about some things regarding the GPL license. I understand the GPL allows a person to do almost anything with the software (limited restrictions), however the condition is that in many cases the new software you make which includes GPL software must be made open source, or at least available to anyone who requests the source. I understand this is what Flight Pro Sim has done. They have made their product a commercial one, but must provide the source for anyone who requests it.
My question is a little less simple than the above case, because the GPL as I understand was mainly written (if I understand correctly) to affect software, ie., code, programming. My question is about the 3D models, which are also licensed under GPL.
If for example I make a game and I include an aircraft from FlightGear in it, it doesn't make much sense to talk about making the source code available because what I've used in it is just the 3D models and textures. Unless it is required that the source code of my entire game must be made open source. I am wondering if this is required.
Likewise, if I have my own 3D model of a plane in my game, and I wish to use the cockpit models and textures from a FlightGear aircraft, what is it exactly that I need to make publicly available. I am happy to make available any models and any changes I make to it (for example a cockpit or a plane), but by doing this, does it mean that I need to make publicly available the entire plane? Or the entire game open source?
As another concrete example, there is a popular contributor here with the username Helijah, who has his own hangar, who has made his aircraft available for download on Sketchfab under a CC BY (attribution) license. If I were to use this aircraft in my game, I would have to attribute Helijah. No problem there. But say I used a cockpit from another of the aircraft here (which are licensed under GPL as far as I know), does that mean my game has to be open source? Or that any plane I use the cockpit in has to be made publicly available?
Thanks in advance for any information about this. Licenses can get pretty complicated.