[vtk-developers] vtkPowerCrustSurfaceReconstruction

Miller, James V (Research) millerjv at crd.ge.com
Thu Jul 11 16:36:40 EDT 2002


Ken,

It looks to me that the Marching Cubes patent was filed 6/5/1985 and issued 12/1/1987.

According to http://www.ssjr.com/interact.htm the expiration date is 6/5/2005.

According to http://www.lectlaw.com/files/inp03.htm patents filed after 1995 will
last 20 years from the point of filing. For (some) of the patents filed prior
to 1995, the patent will be in place for the longer of 

1) 17 years from date of issue
2) 20 years from the filing date of the first US patent application on which
this patent is based

Here is snippet from the above website.

"Under the transitional provisions, the term of a certain group of 
patents will extend for the longer of two alternative calculations: 
17 years from the date the patent issued, or 20 years from the filing 
date of the first U.S. patent application upon which the issuing 
patent is based.  This provision applies to all patent applications 
now pending, to all patent applications filed between now and June 7, 
1995, and to all issued patents that are in force on June 8, 1995. "


Jim


-----Original Message-----
From: Ken Martin [mailto:ken.martin at kitware.com]
Sent: Thursday, July 11, 2002 9:38 AM
To: Will Schroeder; Tim Hutton; vtk-developers at public.kitware.com
Subject: RE: [vtk-developers] vtkPowerCrustSurfaceReconstruction


Hey Folk,

As a general note to all developers. Please be careful not to put any
GPL or LGPL code into VTK. If you know of GPL'd code in VTK, bring it
to our attention so we can correct the situation. In most cases where
we have wanted to add GPL'd code, the authors of the code have been
willing to let us use it under a BSD type license (which is the same
basic license as VTK). Since it sounds like the folks at the
University of Texas disagree we cannot use their code. (which is a
shame because having their algorithm in VTK brings advantages both to
VTK and to them) We could use a reimplementation of their algorithms
based on their papers as long as they have not patented their
algorithms (since they said is was publicly funded I assume they would
not patent it, but it is best to check). Frequently by the time the
code has been fully integrated and cleaned up it is almost a rewrite
anyhow. If you end up doing a rewrite it is worth documenting that it
is a clean implementation done at U of T's insistence. I'm sure it
would be a popular class.

On a related note for long term planning. I am suggesting removing the
patented directory and classes at the end of next year. The key
algorithm in the patented directory is marching cubes and its patent
expires Dec 2003. At that point I'd like to move that code into the
main tree and remove the other patented classes, which I do not think
the VTK community should be maintaining. That will also clear up a
number of patented, questions, issues, etc. and make VTK all fall
under a BSD license with no exceptions.

Thanks
Ken

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