Hi Chuck,

What you'll need to do is add a Polytope into the CullVisitor to test
each node against, or adjust the view frustum polytope to be smaller
than the view frustum for that subgraph.

I haven't ever tried the type of thing you are after, but the
osgUtil::CullVisitor/osg::CullStack classes do support view frustum
and a list of occlusion culling polytopes, perhaps the later could be
co-opted to do what you want, it'll be doing the reverse of a
occlussion culling polytope (culling outside rather than inside) but
this can be handled by making sure the normals of the planes of the
polytope are point inside just as they do for the view frustum.

A cull callback above your scene graph might be able to add in your polytope.

Robert.

On 6/18/07, Chuck Sembroski <[EMAIL PROTECTED]> wrote:



Hi all,


This is probably an easy question.  I have a collection of absolutely
gigantic OpenInventor files.  I would like to load and display only a tiny
portion of the geometry, clipped by a bounding box.  In the past I would
have simply setup hardware clipping planes to accomplish this.  But in this
case, I would rather not send a massive amount of geometry down the pipe,
only to draw perhaps 1% of it.

I looked in osgUtil but didn't see the sort of software-based clipping code
I was looking for.  Has someone done this already?


Chuck ________________________________
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