Hi Robert,
many thanks for your reply.
If I understand it right, the VPB creates a hierarchy of static LOD
nodes that are paged.
But is it possible to use the VPB for generation of such graph for
general datasets, not only terrain data?
I have an large triangle mesh on input, let's say in STL format (can
convert to OSG Geode or custom vectors).
How can I give such input to VPB and get an PagedLOD hierarchy osga on
output ?
Simply generate osga and put it as input file (is it the
vpb::Source::MODEL)?
In the osgdem source I see the line
osg::ref_ptr<osg::Node> node = osgDB::readNodeFile(fileName);
does it mean that the input file must fit into the memory to process it?
Many thanks,
Tomas
Robert Osfield napsal(a):
Hi Tomas,
On Tue, Oct 14, 2008 at 2:07 PM, Tomas Hnilica
<[EMAIL PROTECTED]> wrote:
does anyone know about dynamic Level Of Details implementation in OSG?
The VirtualTerrainProject is based ontop of the OpenSceneGraph and
adds a number of CLOD techniques.
There are well described algorithms like several types of Hoppe's
Progressive Meshes or Garland's Quadric Error Metrics.
I am wondering if no one made an OSG implementation (or is there some major
problem for such dynamics in scenegraph?).
No problem in implementing them, but... these days CLOD is not as
compelling a solution than it once was. Paged databases scale much
better - for instance the combination of VirtualPlanetBuilder and OSG
is currently being used to generate and view multi-Terrabyte whole
earth databases.
The chunkLOD by Vladimir Vukicevic referenced on vterrain.org is not
available.
chunkLOD is not a CLOD implementation, it's a paged system, since the
OSG has paging built into and it has VPB to build databases you
basically have something like chunkLOD right out of the box, and in
system that is far more flexible.
Also the Demeter project is not available on http://www.terrainengine.com,
but I found it on http://www.tbgsoftware.com/downloads.html. Anyway it's not
a general dymamic LOD, but it's mainly for terrains.
I never found Demeter to perform well so wouldn't recommend it so the
lack of availability of Demeter is probably not too much of a
hindrance.
Robert.
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