[Bf-committers] GPL + Python, revisited
Ton Roosendaal
ton at blender.org
Tue Mar 31 15:07:41 CEST 2009
Hi,
Still not much news from FSF on the topic, apparently it's not simple
for them either.
I proposed to them (and to this list now) to make the following
official FAQ statement on the Blender Python license;
(Explanation follows, scroll down)
----------------
* Licensing Blender Python scripts
When a script uses calls that are part of the Blender Python Script
Language, the interpreted program, to the interpreter, is just data;
you can run it any way you like, and there are no requirements about
licensing that data to anyone.
The Blender Python Script Language is defined here:
http://www.blender.org/documentation/248PythonDoc/index.html
This is true only and if the script doesn't use "bindings" (calls to)
to other libraries or facilities that are GPL licensed.
The GNU GPL defines that combining GPL licensed software (like
libraries, static or dynamic) via an interpreted script, effectively
will make the script GPL-compatible too.
http://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL
In case you link a Blender Python script to modules, libraries,
plug-ins or programs that are not compatible with the GPL license, the
GPL license defines they form a single program, and that the terms of
the GPL must be followed for all components when this case gets
distributed.
* Licensing Blender .blend files
The output of Blender, in the form or .blend files, is considered
program output, and the sole copyright of the user. The .blend file
format only stores data definitions.
In case you embed the .blend file with Python scripts, and the scripts
provide bindings to other libraries or facilities, the above topic
applies.
* Disclaimer
The above statements are not yet officially confirmed by the Free
Software Foundation. In case the FSF concludes there's a conflicting
situation with the GNU GPL, the Blender Foundation will seek efforts to
include an amendment in Blender's GNU GPL license to secure this, based
on permission from all contributors, and relying on BF's compilation
copyright.
-----------------
Note: Once 2.5 is out, we can also limit a license amendment to the 2.5
Python API, making it less complicated to get the contributors to agree
on it.
The basic thought behind this proposal is to ensure that all artistic
output that's stored in a .blend file, remains the sole property of its
creator. Python constraints, logic scripts, procedural objects, custom
editors or exporters included.
However, if you extend Blender - via Python - to link to other programs
or libraries, you have to follow the letter of GPL still. This
extension simply occurs when your code doesn't run anymore in the
Blender script interpretor.
What this would enable is for example:
- Companies posting exporters or importers under own copyright and
license conditions.
- Studios creating a Blender configured level editor, with proprietary
file exporting, and limit distribution of these scripts or .blends to
own relations only.
What is *not* possible then:
- Offering the Blender binary with own scripts under a single closed
license.
- Combining the Blender Player with a .blend file, under own license.
- Or in general, limit distribution or usage of Blender in any way
other than GPL. :)
-Ton-
------------------------------------------------------------------------
Ton Roosendaal Blender Foundation ton at blender.org www.blender.org
Blender Institute BV Entrepotdok 57A 1018AD Amsterdam The Netherlands
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