The full text of the GNU General Public License is available here. This section tries to explain the implications for Blender users.
The GPL license gives end-users additional rights that are normally reserved to the copyright holder, such as distributing and making copies of work (in this case Blender), make derivative works (ie add new features to Blender), and the freedom to sell the work to others. These additional rights are granted as long as the end-user also grants these same rights to their end-users under the terms of the GPL, and as long as the individual abides by the terms of the GPL.
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.
The Python scripts that are part of the Blender distribution are fully
GPL compliant.
When you write Python scripts which use parts of the Blender API, the
scripts are considered to be "acting as one program", so when you
publish such scripts they have to be GPL compliant as well.
That is correct, games are program output and therefore not covered by
the GPL. The Blender team is committed to making sure that Blender can
be used for both GPL and non-GPL games without any license conflicts.
With stand-alone games however, any data that is included inside the
actual stand-alone executable is covered by the GPL, if this is a
problem then you should set up the stand-alone player so it reads from
external .blend files.
A screenshot can show a mix of GPL content (Blender GUI) and your own artwork. For that reason you can consider a screenshot to be entirely GPL artwork. However, Copyright law in different countries actually differ in this area. Please consult legal advice if you're unsure.
In almost every circumstance for blender, only the code and other GPL'd files themselves are covered. Any output of such material is copyright the person who produced the output, in this case, the artist.
The splash-screen and icons are GPL'd material therefore when using
them the terms of the GPL must be followed. Usage of the Blender Logo
is only GPL too when used within the context of screenshots of the GUI
with or without splashscreen.
(More information on usage of Blender logo will follow later)
Of course, you may give any of the versions of Blender on Blender3d.org or Blender.org to your friends. After 2.25 every version of blender can be distributed under the GPL. Most of the older versions as well, so long as they aren't the old NAN builds.
Yes, but if you make modifications you must comply with the GPL and if they request the source code you have to distribute that to them as well. You can charge for the version of blender you give to your friends even, but it must be licensed under the GPL, and you may not charge an unreasonable fee for the source code.
Blender becomes better because of valuable code contributions, we encourage your organization to contribute your code back unless it is absolutely vital. However the GPL does allow your organization to use a modified version of Blender internally without offering the source-code as long as you do not distribute it outside your company or organization.
The GPL allows for developers to work on blender without worry that their work could be put into a closed application. The GPL makes it so that all contributers must make their code open, this means that if someone distributes a version of blender with a cool feature, everyone can have it.
From an artist's perspective the openness of the community that forms around an open-source project is probably the best thing. An open community and development process allows artists to directly talk with programmers, if there's a feature that an artist needs, he or she can directly e-mail a developer about it. If an artist encounters a bug that needs fixing, he or she can track it in the bug tracking system.
The only disadvantage to open-source is that you are mostly on an even playing field because everyone has the same rights that you do to the software you're using. This means that you have to actually produce superior artwork in a competitive environment and can't just relay on superior technology. Depending on your view of things, this may be an advantage.
Artists are using products under the GPL. My favorite saying about why we don't hear about them more often is because they're busy using the products in their job. Many people develop this code because they need this code, many artists use blender and don't feel the need to post all over the web about it, because it's the art that's important.
OpenEXR is a project from Industrial Light and Magic, it is licensed under the a modified BSD license. Many firms contribute to some of the more advanced open-source graphics software. Open-Source licenses are being used in greater frequency by large graphics firms.
Disclaimer: This document is no substitute for legal advice and just represents a subset of possible interpretations of the law and the GPL.