Robert, Thank you for the advice! I actually am using a scheme almost identical to the one you mentioned. The only differences are that I'm using PagedLODs, I'm using display lists (in addition to VBOs), and I have matrix transforms that are applied to the geometries. I'll try going without the PagedLODs and seeing what happens. If you don't mind, I'd like to clarify a couple things before proceeding:
1. When you say spatially segmented, I'm assuming you mean that the points in each osg::Geometry should be close in proximity. But do you also mean that the scene graph should be organized spatially in a quad- or oct-tree structure of osg::Groups? 2. I have some datasets with over 100 million points, so I'll need to use PagedLODs at some point. When you say that the DatabasePager should be set up to achieve a variable frame rate, do you mean that I should call setUseFrameBlock(false)? Thanks, Andrew -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robert Osfield Sent: Tuesday, July 04, 2006 4:21 AM To: osg users Subject: Re: [osg-users] Displaying lots of point data Hi Andrew, I'd recommend breaking your dataset into chunks of vertices, ideally spatially segmented, with each chunk a seperate osg::Geometry containing a single DrawArrays. You should use VBO's on these geometries (see osg::Drawable header for details) and play around with how many vertices per geometry provides the maximum throughput. I've worked with over 10 million vertices these way at interactive speeds. Once you get to to around this number you won't be able to fit all the data on graphics card so it'll have to start paging the data in from main memory - this is where having bite sized chunks will make all the difference to performance. I did try paging the data but found that the DatabasePager had to be set up to download the data to GPU as quickly as possible, rather than get it to try and achieve a constrant frame rate, as the big chunks take too long to download otherwise. If you can get away with not using PagedLOD then you'll probably find things work just fine. Robert. On 7/3/06, Andrew Weitz <[EMAIL PROTECTED]> wrote: > Robert, > > At the OSG course in May, I asked Don about displaying huge amounts of > point data. He recommended I write you an email because he's seen you > do cool things with point clouds in the past. > > I currently create point clouds by passing a vertex array to a geometry > and adding a GL_POINTS primitive set. I create IVE files of point > clouds, each with about 25,000 points. These get added to my scene > graph as paged LODs. The problem is that when my point count gets up in > the several hundred thousand range, visualization becomes much too slow. > I'd like to be able to view millions of points if possible. > > Do you have any recommendations for displaying huge amounts of point > data? > > Thank you! > > Andrew > _______________________________________________ > 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/
