Hi Robert, Going back to scene graph? > have I to create 1) a scene with one geode for each geometry? or 2) only one > geode containing all N geometry?
My question is: Why do the two solutions seem to behave in the same way? Should the first way better fot "frustum culling phase"? I thought each geodes (leaf node) had own boundig volume used by the OSG to chose which geometry render... THANKS. On Tue, May 6, 2008 at 3:32 PM, fabio riot <[EMAIL PROTECTED]> wrote: > About your advice...(how to render 12000000 triangles file,ply) > Once I break the model into smaller geometry (for example N=200 > geometry blocks with 60000 triangles), > have I to create a scene with one geode for each geometry? or only one > geode containing all N geometry? > > I thought the first solution was the best...but trying both I'haven't > noticed difference in frame rate Your biggest bottleneck will be the GPU, which is down to granularity and the way that you pass your data. The exact way you hang the Geometries off the scene graph won't matter too much right now as you aren't CPU limited, later on once you have the GPU side working efficient you might see CPU overhead being an issue, then we can look at optimizing the scene graph structure, but right now don't worry about it. 2008/5/9 Robert Osfield <[EMAIL PROTECTED]>: > Hi Fabio, > > On Fri, May 9, 2008 at 1:00 PM, fabio riot <[EMAIL PROTECTED]> wrote: >> Hi Robert >> Sorry, I haven't much experience in computer graphics...can you >> explain me what you mean with "GPU down in granularity"? > > I believe I wrote: > > "Your biggest bottleneck will be the GPU, which is down to granularity > and the way that you pass your data. " > > By which I mean the performance you get will mostly depend on > > 1) the granularity of the data i.e. how big Geometry chunks you use > 2) the use of VBO's, DisplayLists, glDrawElements etc. > > W.r.t granularity I recommend that you experiment with the size of > osg::Geometry (i.e. number of traingles > per Geometry) to see what sweet spot you get, it'll be driver/hardware > dependant so try it on a variety of > machines. > >> However I have tested the program in Windows XP 32 bit (precedent test >> was made in Vista 64 bit) >> and now I can use VBO and DL also for larger dataset (maybe the GPU >> driver aren't efficent in VISTA). >> The only side effect is with DL, for larger model ,some piece of >> geometry aren't rendered. > > I believe both the driver model and the driver implementations are > problematic under Vista, if you want best performance right now you > are probably best sticking to XP, or just move up to Linux, here the > compilers, OS, filesystem, threading support, memory management are > all better than any of the Windows OS's. > >> To improve frame rate is possible to use a decimate model during the >> movement (rotation ,zooming..) >> switching on complete model in motionless state? > > Just you can do this, such as by using a Switch which is manually > controlled, or perhaps a callback that monitors the view matrix and > automatically switches between low res and high res children. You'll > need to the decimentation of course, osgUtil::Simplifier could help > you out here. > > Robert. > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
