Michael T. Jones (mtj++at++intrinsic.com)
Wed, 17 Nov 1999 12:07:18 -0800
This question is interesting because people seem to use the word "cull" in
two opposite senses. To cull is to choose, or to select from a group, as in to
identify those nodes partially or fully with a view frustum for display. The
OED offers this usage "It's a collection of fascinating stories culled from a
lifetime of experience." There is a second meaning, which is to to kill
animals, especially the weaker members of a particular group, in order to
reduce or limit the number of them. It is also used figuratively. From the
OED, "She is likely to be one of the few ministers to survive the Prime
Minister's annual ministerial cull. You might think that the cull process
"searches out and destroys" nodes outside the frustum and mean it that
way too.
So, if you mean cull as select, then disabling culling is "to never select"
and a switch node, or bogus static bounding sphere (the size of a pea but
way away from the camera, like on mars) does the job fine. In that case
you want the node up near the root so that parent spheres are not made
too big needlessly.
If you mean cull as kill, then disabling culling is to always select. To do
that you can make a bogus static bounding sphere too, but this time you
want something huge, like the size of the universe. In this case, you also
want the node near the root so that intermediate nodes are not bloated.
Michael
----------
Michael T. Jones - <mailto:mtj++at++intrinsic.com>mtj++at++intrinsic.com -
<http://www.intrinsic.com/>Intrinsic Graphics Inc. - (650) 210-9933x13
A frog in a well says "The sky is as big as the mouth of my well"
At 09:00 PM 11/17/1999 -0500, Devrim Erdem wrote:
I would like to disable culling for a specific
node in the scene. Is this possible ?
This question is interesting because people seem to use the word
"cull" in
two opposite senses. To cull is to choose, or to select from a group, as
in to
identify those nodes partially or fully with a view frustum for display.
The
OED offers this usage "It's a collection of fascinating stories
culled from a
lifetime of experience." There is a second meaning, which is to to
kill
animals, especially the weaker members of a particular group, in order to
reduce or limit the number of them. It is also used figuratively. From
the
OED, "She is likely to be one of the few ministers to survive the
Prime
Minister's annual ministerial cull. You might think that the cull
process
"searches out and destroys" nodes outside the frustum and mean
it that
way too.
So, if you mean cull as select, then disabling culling is "to never
select"
and a switch node, or bogus static bounding sphere (the size of a pea but
way away from the camera, like on mars) does the job fine. In that
case
you want the node up near the root so that parent spheres are not
made
too big needlessly.
If you mean cull as kill, then disabling culling is to always select. To
do
that you can make a bogus static bounding sphere too, but this time
you
want something huge, like the size of the universe. In this case, you
also
want the node near the root so that intermediate nodes are not
bloated.
Michael
This archive was generated by hypermail 2.0b2 on Wed Nov 17 1999 - 12:07:29 PST