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   <H1>[Nel] culling and transforms</H1>
    <B>Lionel Berenguier</B> 
    <A HREF="mailto:berenguier%40nevrax.com"
       TITLE="[Nel] culling and transforms">berenguier@nevrax.com</A><BR>
    <I>Mon, 2 Jul 2001 11:14:03 +0200</I>
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<PRE>----- Original Message -----
From: &lt;<A HREF="mailto:stephane.craux@voila.fr">stephane.craux@voila.fr</A>&gt;
To: &lt;<A HREF="mailto:nel@nevrax.org">nel@nevrax.org</A>&gt;
Sent: Saturday, June 30, 2001 12:21 PM
Subject: [Nel] culling and transforms


&gt;<i> Hi ,
</I>&gt;<i> I Just took a look at nevrax code recently and
</I>&gt;<i> noticed that rather than transforming AABB when traversing
</I>&gt;<i> the scene graph , the choice was made to transform the
</I>&gt;<i> view frustum pyramid : it is much more cpu costly :
</I>
Is it not nearly the same?

transform the planes:  transform 6 planes =&gt; 6*16= 96 muls.
transform the AABB:  transform 8 vectors =&gt; 8*12= 96 muls.

But maybe your trick to transform an AABB is to just transform the center
(12), then transform the 3 half vectors of the AABB (3*3 because of their
axis form), and then just do some add ?  (ooops :) )

regards

Lionel.


</pre>








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