I'd just like to echo Gavin's sentiments. I've only been looking at Paradox for the past day or so, but so far it feels like everything I want in a C#-targeted game engine. The "game studio" front end is very similar in nature to UE4, albeit at a much, much earlier stage of development; it's basically a proxy for File->New Solution that you'd use in Visual Studio; it creates the solution and platform-targeted projects, which you then open in Visual Studio and get to work. It doesn't generate masses of boilerplate code which is awesome as I wanted something that felt somewhat minimal when starting from scratch. On top of that the game studio basically provides an asset manager and compiler, and when you make changes, Visual Studio detects the file changes and prompts you to reload the affected files, which makes the whole process pretty clean. The solution and project format is pretty reminiscent of the way Xamarin projects work; you have a core project and then a targeted project for each platform you want to support. Internally the API shares a lot of similarities with MonoGame, and provides very easy APIs for handling both 2D and 3D rendering. The team seems really active in developing the engine too. All in all, quite impressed.

Regarding the licensing discussions, my understanding is that if you want to modify the engine itself, then yeah you have to contribute those changes back to the engine, which is fair enough seeing as you're using it for free. However if you use their signed binaries, which really is the default way of working with Paradox anyway, then you have no obligation to share your code with anyone, whether your project is commercial or non-commercial.

Regarding the licensing discussions, my understanding is that if you want to modify the engine itself, then yeah you have to contribute those changes back to the engine, which is fair enough seeing as you're using it for free. However if you use their signed binaries, which really is the default way of working with Paradox anyway, then you have no obligation to share your code with anyone, whether your project is commercial or non-commercial.

You don't have to contribute your changes, the GPLv3 only requires you to provide the sourcecode to those who buy or receive binaries from you (in practice it is easiest to just make it available to everyone since one of your customers will eventually do that anyway but there is no such requirement), code you release under the GPLv3 may not be used in the proprietary version of the engine without your permission.

If you want them to include your fixes/improvements/changes in the official version however you will need to give them additional rights (as per their contributor agreement) and if they don't include your changes in the official version you will have to re-integrate them each time you upgrade the engine (effectively forcing you to maintain your own fork of the engine which can be quite alot of extra work)

Stop beating the dead horse guys, Bacterius already quoted the relevant part like 10 posts ago. Read the thread.

We gladly accept external contributions. Feel free to submit us pull requests and we will consider them for inclusion.

Contributors will need to sign electronically a Contributor License Agreement, available here (based on Harmony). It allows us to use your changes in the commercial version, and relicense code easily (in case we decide to go MIT at some point for example).[/quote]