From guest  Thu May 26 15:10:13 1994
From: aaron@qbert.dseg.ti.com (Aaron Hightower)
Subject: pfPartition
To: iris-performer@sgi.sgi.com
Date: Thu, 26 May 1994 17:12:53 -0500 (CDT)
X-Mailer: ELM [version 2.4 PL23]
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Status: OR

-------------------
From jim helman:
-------------------
Subject: Re: Large MultiGen/Performer databases
Date: Wed, 20 Apr 94 20:11:23 -0700

It's always best to spatially organize the scene graph
for culling.  pfPartitions speed up intersection
traversals, e.g. terrain following, but do not affect
culling.                                ^^^^^^^^^^^^^

rgds,

-jim helman
-------------------
From the man page:
-------------------

DESCRIPTION
  A pfPartition is a type of pfGroup which organizes the scene graphs of
  its children into a static data structure which can be more efficient for
  culling and intersections.
  ^^^^^^^
--------------------

Which is accurate?  What does a pfPartition *really* do?  What, specifically,
is a pfPartition?  Does it modify its children?  Does it splice (divide)
geometry into pieces?  Does it make culling more efficient?

Thanks in advance,
         _                                                      _
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From guest  Wed Jun  8 15:05:30 1994
Return-Path: abramsh@tabor.mitre.org
	id AA24899; Wed, 8 Jun 94 18:05:00 EDT
From: "Howard Abrams" <abramsh@tabor.mitre.org>
Message-Id: <9406081804.ZM19263@tabor>
Date: Wed, 8 Jun 1994 18:04:57 -0400
X-Face: "K/fJ/f?*WE_#;z\|CNp$+h^E2!&gQ81\C'^AU,bHw*Fnw7"kIpq-_CHK*U(9;@W(dH?6A-:K'G#O>"?FJN#x`G^|O[<xAYcX=NpOQ,YK*NBS'3y?le[7E=_>OoJ&\]90&gj,gCE}bd]s%(y9`rVDKoqA(7S$9neB8J7}h;G3P^'7Sz^`:h{[,x->n~e*#'D})GpI"f^l^eiTkXeg+p'J()_<3Rx))]QJ=*p&l8iS~1NjHB49cVV+W/E\9,*rg={To@d;uSmNJ|b<+DSKUSbtc1Z@&@TMM}7vtL{ud!ULX/vbz,^!0HFzcj?p71>9i>&[^ZK`nj~VtL
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To: info-performer@sgi.sgi.com
Subject: pfPartition
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Status: OR


No one ever answered the question about pfPartitions. Do they, or do they
not, speed culling? The man page says 'yes', but someone had said 'no'.

Howard

-- 
Howard Abrams (abramsh@mitre.org)                       The MITRE Corporation
Mail Stop W273                              Interactive Simulation Technology
The Mitre Corporation                                 I-Lab Envisioning Group
McLean, VA 22102                                         Phone (703) 883-7421 

     These are not Mitre's opinions.... Hell, they're not even mine!




From guest  Thu Jun  9 18:22:48 1994
Message-Id: <9406100116.AA14440@surreal.asd.sgi.com>
To: "Howard Abrams" <abramsh@tabor.mitre.org>
Cc: info-performer@sgi.sgi.com
Subject: Re: pfPartition 
In-Reply-To: Your message of "Wed, 08 Jun 94 18:04:57 EDT."
             <9406081804.ZM19263@tabor> 
Date: Thu, 09 Jun 94 18:16:19 -0700
From: Jim Helman <jimh@surreal>
Status: OR


pfPartitions are only currently intended to improve
intersection performance.  For culling they behave
exactly like a group.

It appears that there are some bugs in 1.2 regarding
pfPartitions.  I'd advise against using them until we
work through the pproblems.

rgds,

-jim helman

jimh@surreal.asd.sgi.com
415/390-1151