Hi Jimmy, I also use VPB and osgTerrain with 500GB+ databases. Genereally you are right, NTFS isn't the best database for handling folders with lots of files.
But I think you mix up two different aspects: In my opinion the handling capability of large file numbers is another topic than loading performance. My experience is: - NTFS can handle large numbers of files - Windows explorer has problems to move/copy so many files, the file management ist poor. Once the files are finally written to disk it's fine. To your original problem: I think you optimize your system too hard along that one parameter: the reduction of files to load. The small tiles are not default settings for fun: with large tiles you thwart the LOD algorithm an finally have much more vertices to render than with small tiles and good LOD'ing. As Robert said, 2000 x 2000 heighfield tiles is way to large, it makes 4000000 vertices per tile! The loading of you tiles shouldnt affect your rendering frame rate. As Robert said, OSG uses several seperate threads only for loading files from disk and preparing them to be rendered. If you "order" a tile and this tile is loaded to late (by whatever reason), it will be loaded simple in the next frame, but the rendering thread would not wait for it to be loaded. After the pager has loaded the tile and passes it to the rendering thread to render it, it has to deal with several potential performance bottle necks: - The first time the tile should be rendered, the geometryTechnique has to create a renderable geometry (triangle mesh) of the heightfield. This seperation of data storage in the tiles and data interpretation during rendering introduces a great flexibility but also some calculation needs which can not be preponed into the VPB processing stage. - Another bootleneck could be the grafic hardware. As robert said on some point in the rendering stage the data has to be transfered into the grafics hardware to be rendered, because the data is loaded but still in CPU and not GPU space. Unlikely, but that may be a booteneck too. If you fly and you have to load a lot of new tiles, one of the the bottlenecks may cause your lag. Remember, every calculation regarding a single tile is way more performance comsumptive if your tiles are so large. I think OSG provides a mechanism to control how many data is compiled in each frame. Also here using smaller tiles allows OSG a much finer grained control. If I'm wrong in some thoughts, please correct me :) Thank you! Cheers, Torben ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=42444#42444 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
