I'm mostly concerned about using GtkRadiant for commercial purposes. I've read on the Internet that in the eula of GtkRadiant it is stated that in order to use GtkRadiant for commercial purposes, one must buy a licence from id Software. However I suspect that this might have changed, since I couldn't find this eula anywhere within the GtkRadiant package. Does GPL licence imply anything on created content using the GPL'ed software? Or do the programs have their own terms on created content?

Quote: Original post by Giedrius
Does GPL licence imply anything on created content using the GPL'ed software? Or do the programs have their own terms on created content?

Yes GPL is copyleft and requires that you licence code under GPL or a compatible licence. AFAIK this does not effect the content which you create using a GPL program.

Quote: id Software's Quake III Arena is and was a very popular game. The company released the full source code last year. Some months later, they released the source code for the popular level editor "GTKRadiant". This tool allows you to create levels for several games, e.g. Half Life 1, the Quake- and Doom-series. So it is a wise decision to use this great and proven tool to build your levels. Additionally, id Software allows the use of their file formats and tools for every project you want. However, for a commercial project, you have to write your own tools to create the files. The latter constraint is nullified with the release of the source code under GPL license

source

Quote: Original post by Giedrius
Does GPL licence imply anything on created content using the GPL'ed software? Or do the programs have their own terms on created content?

The license refers only to the source program itself. It has no bearing on how you use the product. The GPL itself has always been very clear on that point, even in the first version.

The license is strictly limited to the use and distribution of the program.

The GPL is very clear that you may not add additional restrictions. Each revision of of the GPL has clarified that you may grant additional rights that you control, but not add additional restrictions.

The use of GPL-licensed software does not have any impact on the things you create, record, edit, or otherwise manipulate using those tools. If you legally acquire a piece of software under the GPL, you may use it for any legal purpose without restriction; commercial or not.

As far as I know, you can used GPL tools for commercial product without any licenses(unless specifically stated). For instance GIMP is released under GPL however does mean that anything I create with it is also under GPL. Now if I modified the actual GIMP source code, that would become GPL and I would have to release that freely(but that does not mean you can't also sell it, just look at linux distro like redhat or Suse).

Quote: Original post by 3dmodelerguy
For instance GIMP is released under GPL however does mean that anything I create with it is also under GPL.

No.

Again, The GIMP source and therefore the application is released under the terms of the GPL.

Nothing else is touched by the GPL.

The GPL does not affect your artwork, your scripts, your brushes, patterns, or any other content you create with the tool. You have all rights associated with them.

The GPL only touches The GIMP program and its source code.

Quote: Now if I modified the actual GIMP source code, that would become GPL and I would have to release that freely(but that does not mean you can't also sell it, just look at linux distro like redhat or Suse).

Almost.

The GIMP source and therefore the application is released under the terms of the GPL.

In that case you have created a derivative work. IF you release or publish your changes (either as source or binary form) you must release it under the terms of the GPL. If you never release or publish your changes, it does not affect you. For example if you use a modified build within your own company or group, but never publish or distribute it further, you never need give up your source.

You may charge for media and certain other fees, as specified by the GPL.