license.html

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title: The CGAL License
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<p>Since release 3.0, CGAL is available under an
<a href="http://www.opensource.org/">Open Source</a> license as well as a
commercial license.  Users choosing to use CGAL under the free-of-charge Open
Source license have to comply to its terms, otherwise they have to buy a
commercial license.</p>

<p>Releases 3.x were distributed under the <a href="https://opensource.org/licenses/QPL-1.0">Q Public License</a> (QPL)
and <a href="https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html">GNU Lesser General Public License, v2.1</a> (LGPL).
Starting from release 4.0, CGAL is available under the
<a href="https://www.gnu.org/licenses/gpl-3.0.en.html">GNU General Public License</a> (GPL) and the
<a href="https://www.gnu.org/licenses/lgpl-3.0.en.html">LGPL v3+</a>. These license changes
are not fundamental as the licenses are similar in their spirit. These changes
only reflected the fact that the QPL had become marginal, since it had
been introduced by <a href="https://www.qt.io/company">The Qt Company</a> (formally known as <i>Trolltech</i>)
for their free version of <a href="https://www.qt.io/what-is-qt/">Qt</a> and was later abandoned.</p>

<P>
We informally describe below our license scheme and the rights we give
to our users. Do not hesitate to <a href="mailto:info@cgal.org">contact us</a> if you have any question regarding the licenses.</p>

<H2>The Open Source License</H2>

<p>Some parts of CGAL are available under the LGPL, whereas other parts are under the GPL.
These two licenses introduce different constraints.</p>

<P>
The idea is that the fundamental building blocks of CGAL are under the LGPL
because this is a less constraining license which allows more people to
build on top of this code without much constraints.  This helps making
the CGAL design a de-facto standard for geometric code which helps
interoperability.  The higher-level algorithms are typically released under the
GPL in order to protect their commercial value.  This makes it possible for us
to exploit it commercially, which guarantees long term support, maintenance and
further developments of the code for the benefit of the project and its users.</p>

<P>The <a href="http://doc.cgal.org/latest/Manual/packages.html">Package Overview</a>
web page gives the license of each package.  Approximately, the Kernel and
Support libraries are under the LGPL, and most geometric algorithms and data
structures are under the GPL, but there are some exceptions in both directions.

<p>For the exact and formal details of the license, please always refer
to the <b>LICENSE</b> file from the CGAL source code distribution.</p>



<H3>The LGPL</H3>

<p>The <a href="http://www.gnu.org/copyleft/lesser.html">Lesser General Public
License</a> (v3+) gives you the right to use and copy the code freely. It is also
possible to modify the code under the condition that the resulting modification
is released as source code under the LGPL with any binary distribution of 
your software that uses these LGPL parts.</p>


<H3>The GPL</H3>

<p>The <a href="http://www.gnu.org/copyleft/gpl.html">GPL</a> (v3+) is an Open Source license 
that, gives you the right to use, copy and modify the code freely. If you distribute 
your software based on GPLed CGAL data structures, you are obliged to distribute the 
modifications of CGAL you made, and you are furthermore obliged to distribute 
the source code of your own software under the GPL.</p>




<H2>The Commercial License</H2>

<p>In cases where the constraints of the Open Source license prevent you from
using CGAL, you can buy a commercial license for CGAL or parts of CGAL
from <a href="http://geometryfactory.com/">GeometryFactory</a>.  The
commercial offer is adapted to academic/research and industry customers.</p>