I think you mean that if you enhance the software or sell it then you have to provide a cut. In general, you don't have to give a cut for works that have been produced with said software.
BTW, Blender is pretty standard in this regard.
"Anything you create with Blender - whether it's graphics, movies, scripts, exported 3d files or the .blend files themselves - is your sole property, and can be licensed or sold under any conditions you prefer." [1]
BTW, Blender is pretty standard in this regard.
"Anything you create with Blender - whether it's graphics, movies, scripts, exported 3d files or the .blend files themselves - is your sole property, and can be licensed or sold under any conditions you prefer." [1]
[1] http://www.blender.org/education-help/faq/gpl-for-artists/#c...