[SciPy-dev] Python (Enthought Edition) for Windows test release

John Hunter jdhunter at ace.bsd.uchicago.edu
Fri Jan 28 22:36:17 CST 2005

>>>>> "eric" == eric jones <eric at enthought.com> writes:

    eric> http://public.kitware.com/pipermail/vtk-developers/2002-July/001755.html

    eric> and

    eric> http://public.kitware.com/pipermail/vtk-developers/2002-July/001763.html

    eric> They mention Dec 2004 and June 2005.  We can either do some
    eric> digging to be sure Dec 2004 is right, or we can wait until
    eric> June and then turn on the expired ones then...

    eric> For now, I am happy to keep them turned off.

Hey Eric, 

My read on that discussion is that Dec 2004 is the proper date.  Bill
Lorensen suggested marching cubes was patented through June 2005, and
then Ken Martin responded

  Actually we are both wrong.  I added incorrectly. It expires
  December 2004 not 2003. The 20 year rule is for patents filed after
  1995.  I included a brief desc below.

and cited

  Utility and plant patents issued prior to June 8, 1995 expire 17 years
  from the date of issue with the payment of maintenance fees.

Since marching cubes was issued on December 1, 1987 [1], despite some
beer jokes that follow in the thread you linked, Dec 2004 appears to
be the right answer in the eyes of the vtk devs for marching cubes.
But dividing cubes was not issued until Dec 5, 1989 [2], which in my
read means its protected until Dec 5, 2006.

All of this of course hinges upon the claim that these patents both
indeed expire 17 years from date of issue, and despite the fact that
I've stared for a long while at the helpful link [3] Robert provided,
I can't really figure that one out.  As an aside, on an unrelated
quest to find out if marching squares was enforceable, an enterprising
matplotlib user contacted GE corporate counsel Carl Horton for
clarification -- his response was less than edifying, basically
amounting to "show me the money!" [4]


[1] http://patft.uspto.gov/netacgi/nph-Parser?u=/netahtml/srchnum.htm&Sect1=PTO1&Sect2=HITOFF&p=1&r=1&l=50&f=G&d=PALL&s1=4710876.WKU.&OS=PN/4710876&RS=PN/4710876

[2] http://patft.uspto.gov/netacgi/nph-Parser?u=/netahtml/srchnum.htm&Sect1=PTO1&Sect2=HITOFF&p=1&r=1&l=50&f=G&d=PALL&s1=4885688.WKU.&OS=PN/4885688&RS=PN/4885688

[3] http://assembler.law.cornell.edu/uscode/html/uscode35/usc_sec_35_00000154----000-.html

[4] http://sourceforge.net/mailarchive/message.php?msg_id=9890501

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