[osg-users] isolate specific LOD from a VPB generated database

Robert Osfield robert.osfield at gmail.com
Tue Nov 29 10:55:27 PST 2016

Hi Nick,

On 29 November 2016 at 18:20, Trajce Nikolov NICK
<trajce.nikolov.nick at gmail.com> wrote:
> I need the idea this time :-) .... This hurts my head for few days already
> :-)
> As the subject says, I have VPB database, geocentric. And this is quad tree
> with many LODs and it is PagedLOD based. How to isolate specific LOD and
> display only that LOD? Quite challenging, uhm ...

There isn't any specific support for this in the OSG so you'll need to
implement it yourself.  Essentially you'll need to traverse down the
database loading subgraphs until you get to the level of interest then
do your operations on that.  The closest example code to doing this
would probably be the intersection utilities in osgSim such as
osgSim::LineOfSight - these intersection utilities have a helper class
that does the loading as the intersection utility drills down into the

The other approach you could take would be to use the naming of the
tiles on disk as a cue to what subgraphs contain the PagedLOD you are
looking for.


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