HI Bruno,

osg::ClipNode is simply a way of position OpenGL clipping planes, it
does no CPU culling what so ever, its purly clipping of OpenGL
primitive down on the GPU.   Using ClipNode will probably harm
performance unless you're fill limited by these trees, which is very
unlikely.

By fat the better approach is place LOD's above groups of trees, and
let the LOD cull out the trees, this will accelerate the cull and
draw.  The way to do it is to partition your forests up in local
groups of say 25 to 250 trees then place LOD's above these.  Tree
different granularity of partitioning to see what works best for your
dataset.

Robert.

On 4/14/07, Bruno Fanini <[EMAIL PROTECTED]> wrote:
Hi all osgusers,

I've set a paged terrain and a Billboard (or many) containing HUGE amount of
trees.
The ClipNode holding the billboard has a plane that is computed depending on
camera position & orientation, so basically trees are clipped out after a
certain distance.

The plane works, but not as I expected: clipped trees (not visible) seem to
be still computed, so there no gain and I get low FPS.

Is it wrong to use ClipNode in that situation?
Should I use other solutions?



--
Bruno Fanini
=====================================================
Graduated Student in Computer Science @ Bologna University (Italy)
WEB :: http://phoenixart.altervista.org
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