Re: Patent 4,734,690

Jason Ozolins wrote:
> Brandon J. Van Every wrote:

>> If the patent was filed in 1983, then in the USA it expired in 2000.

> Sadly, the patent granted is a continuation of one originally filed in 
> July 1984.  The prior art has to pre-date a year before the filing time, 
> apparently.
> 
> The newer patent was granted in 1988.  I don't understand continuations, 

I believe the deal is that you FILE a patent and later it is GRANTED. Under
US law, I think you get protection for 20 years after the patent is FILED
or 17 years after it's GRANTED - whichever is LONGER.   So if you cynically
file a patent - then wait 19.999 years before you do all of the paperwork
to get it finally granted - then you get another 17 years of patent coverage
"for free".  This seems to be the basis of all these 'submarine' patents.

> but wearing my Glasses of Cynicism +5, their effect seems to be to allow 
> you to file a patent before you actually know very much about what you 
> are trying to patent, in order to pre-date any prior art... then to add 
> the necessary details later.

Right.

However, I don't think this patent is about general 3D of the kind we use
in modern applications.  If it was, it would be trivial to find prior art:

eg:
   There were certainly lots of flight simulation applications before 1983
   that did full scale 3D - in hardware - in much the way we do now.

   To take a VERY specific example, the FAA granted 'Level C' certification
   to an Evans & Sutherland 'SP1T' image generator on a Boeing 767 simulator
   in 1982.  Because it was 'certified', all of the government documentation must
   be on file someplace - and all of the detailed technical data for flight
   simulators is carefully preserved as a matter of legal requirement - so
   the defendants in this case should have no trouble finding out how it did
   3D transformations.  This should be ample documentation of the verifiable
   kind that lawyers seem to love.

   Here is some kind of FAA document in Google cache:

   http://64.233.179.104/search?q=cache:5a8rvpvwYqoJ:www.unitedsvcs.com/html/pdfs/b_767.pdf+SP1T+Flight+Simulator&hl=en

   The SP1T image generator hardware had texture, fog and 3D rendering.
   (Although it used an edge-based technique rather than polygons and could
   only render about 200 edges and could only do nighttime scenes).  It isn't
   close to being the first ever realtime 3D graphic system - but it was the
   first thing I turned up with 2 minutes of Googling around.

   Here is a census of all of the flight simulators still in service in the
   world today - (an alarmingly large number of them still use image generators
   from the 1970's and early 1980's with *FAR* less capability than a 3Dfx
   Voodoo-1 card!):

     http://simtechonline.com/Sim%20Census.pdf

   Searching that will reveal 3D graphic systems that are still in service
   that were installed long before 1983.

However, from a brief reading of the patent, I don't think that's what
it's saying. They keep talking about assigning objects to specific "radial
distances" - which isn't something we have anything to do with in modern
graphics.

It seems to me that this might be a patent of some cheap, hacky 2D-ish
approaches to 3D rendering that nobody uses anymore.  This is kinda backed
up by the list of companies they are attacking.  People like Lucas Arts
(for example) did a bunch of games using scrolling/panning backgrounds
and 2D sprites to kinda simulate the effect of 3D using the hardware of
the time.

The patent also talks about 'extensions of the technique' to support
rolling the camera - that wouldn't be something that even comes up with
modern 3D techniques because all three rotational axes just naturally
drop out from the math.

I'm no patent expert - but this patent doesn't worry me.  If it truly
bites us all then it's trivial to find prior art - and if it doesn't
apply to modern games then it doesn't affect what we're doing *NOW*.

That may not be much of a comfort to the people who WERE doing that
kind of stuff in the past.

-----------------------------------------------------------------------
The second law of Frisbee throwing states: "Never precede any maneuver
by a comment more predictive than "Watch this!"...it turns out that
this also applies to writing Fragment Shaders.
-----------------------------------------------------------------------
Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
L3Com/Link Simulation & Training (817)619-2466 (Fax)
Work: [email protected]           http://www.link.com
Home: [email protected]       http://www.sjbaker.org

----- 
FAQ and OpenGL Resources at:
  http://www.geocities.com/SiliconValley/Hills/9956/OpenGL

-- 
Author: Stephen J Baker
  INET: [email protected]

Fat City Hosting, San Diego, California -- http://www.fatcity.com
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [email protected] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB OPENGL-GAMEDEV-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).