[vtkusers] VTK LICENSE CHANGE TO BSD LICENSE

[Berk Geveci]

Dear VTK Users,

Starting with VTK 5.2, VTK will be distributed
under the new-and-simplified BSD License approved by the Open
Source Initiative (OSI).

As you probably know, the OSI (http://www.opensource.org/) is
the community-recognized body for reviewing and approving
licenses as conformant with the "Open Source Definition":

           http://www.opensource.org/docs/osd

As the label of "Open Source" gains more and more positive
reputation, it is important to define very well what the label
means, and when is that the label can be applied to specific
software packages.

The de-facto definition of Open Source today is:

    "to be distributed under an OSI-approved license"

The previous license of VTK, was a modified version of the
traditional BSD license and as such, it was not an OSI-approved
license.

The new VTK BSD license and the previous VTK license differ
only in one of the terms. The previous license has four terms
(or conditions) while the new BSD license has only three.


The terms of the previous license read:
------------------------------------------------------------------
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

------------------------------------------------------------------

==================================================================


The terms of the new BSD license read:
------------------------------------------------------------------

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

    * Redistributions of source code must retain the above
      copyright notice, this list of conditions and the
      following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the name of Ken Martin, Will Schroeder, or Bill Lorensen
      nor the names of its contributors may be used to endorse or promote
      products derived from this software without specific prior written
      permission.

------------------------------------------------------------------


The difference between the two licenses is in the fourth
term of the previous license:

 * Modified source versions must be plainly marked as such, and
   must not be  misrepresented as being the original software.


The license change is therefore equivalent to removing one term
(or condition) and therefore the new license is "more open" (in
the sense that it is less restrictive and impose less conditions
on the recipients of the source code) than the previous license.

We hope that this license change will benefit the great community
of VTK users, and that it will simplify their continued adoption
of the toolkit for research, education and commercial endeavors.

We strongly encourage you, as users of Open Source software to
pay close attention to the licenses of all software (and any other
copyrighted material) that you adopt, to make sure that it conforms
to the expectations of the "Open source" label, as defined by the
Open Source Initiative:

               http://www.opensource.org/docs/osd


Note that previous versions of VTK  are still distributed under the
previous VTK license.


Please don't hesitate to let us know if you have any questions
or concerns regarding the change of the VTK License.


    Regards,

-berk