The LODs should be order from lowest to highest quality. The idea is to get something like: 1) 20KB lod : range = 200 to 1000 2) 100KB lod : range = 50 to 200 3) 5MB lod : range = 0 to 50
As you get closest to the center of the LOD, the pagedLOD node will make requests to load the next child. Because gaps aren't allowed in group nodes, all earlier nodes will be kept in memory up to the current. This means that the net memory usage for the above example would be 120KB when the second lod is visible and 5.12 MB when the highest LOD is visible. Also, if I'm interpreting the pager code correctly, none of the child LODs in a PagedLOD will get paged out until the PagedLOD is flagged as "inactive." It looks as if the culling is used to set that flag, so unless the node is culled for one frame, it will remain inactive and keep all of its children paged in. This could cause problems if a lot of high quality children are ever paged in, but the PagedLOD node itself never gets culled. Even if only low quality children are visible, you'll still be paying the memory price on the higher LODs. Hopefully I'm wrong about that, and Robert can set me straight. Hope that helps, Chase > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:osg-users- > [EMAIL PROTECTED] On Behalf Of Alfero, Kristin > Sent: Wednesday, June 27, 2007 2:43 PM > To: osg users > Subject: RE: [osg-users] OSGpagedLOD question > > Is there a certain way to set up the LOD's that go into the database? It > seems that the LODs are taking up too much memory so when trying to load > it crashes everything. I have more than enough memory and space to run > the necessary database so that's not the issue. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Robert > Osfield > Sent: Wednesday, June 27, 2007 11:16 AM > To: osg users > Subject: Re: [osg-users] OSGpagedLOD question > > Hi Kristin, > > On 6/27/07, Alfero, Kristin <[EMAIL PROTECTED]> wrote: > > I have a question on the OSGpageLOD. I know that it is supposed to cut > down > > on memory using the .ive files, but when I ran my database through it, > it > > completely maxed out all 4 CPUs on my computer and all the memory. Is > there > > something I can do to fix that? > > Do you mean your run the osgpagedlod example on your database? Or > created a database using PagedLOD? > > The whole point of osg::PagedLOD and osgDB::DatabasePager is that they > should help with enable the viewing of massive databases by paging it > in rather than loading all in memory at once. If the database is > poorly conditioned for paging then you won't get best results. In the > case of the example its written to be an example of how to create and > use PagedLOD nodes rather than something generally applied to > databases, I wouldn't expect it work optimally - creating proper paged > databases requires quite a bit of processing, well beyond the scope of > simple example. > > W.r.t CPU's to get maxed out, how many screens/GPU are you using? Is > vsync on? > _______________________________________________ > osg-users mailing list > [email protected] > http://openscenegraph.net/mailman/listinfo/osg-users > http://www.openscenegraph.org/ > _______________________________________________ > osg-users mailing list > [email protected] > http://openscenegraph.net/mailman/listinfo/osg-users > http://www.openscenegraph.org/ _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
