First, thanks everyone for helping me. It's a lot of good information.
Hans, thanks so much for the sample OSG file. It demonstrates the idea of LOD quite well.
Robert, in regard to setting the scale factor for LOD, it seems that passing a value of 2 will affect the entire scene. Is this the case, and if so, is it recommended to this as it will affect all models in the scene?
Thanks for the hints about increasing/decreasing LOD scales in osgviewer. I wasn't aware of that functionality.
Paul, we are using the IVE format, so it has LOD capability. Many of our models have the LOD scale built in to them. Some, however, do not. Our terrain database is a paging database, and increasing the LOD scale inside osgviewer culls the geometry, but the geometry itself is not simplified as our models are. In other words, a model with 1000 polys might be cut down to 200 at a higher LOD scale. However, it seems that the terrain culling is done more in terms of segments than in terms of detail. Increasing the LOD causes portions of the terrain furthest from the eye to disappear, but the underlying polygon mesh does not change. Don't know if that makes much sense or not. Since pictures speak louder than words, I'll attach a couple of small images of the wireframe version of a portion of the database. Saved_image_3.jpg was rendered with an LOD of 1, and saved_image_4.jpg was rendered at a higher LOD.
I wasn't aware of the osgUtil::Simplifier. I will take a look at it.In regard to bottlenecks, I cannot say with any certainty that the polygon / vertex count is my culprit. We are using a 3rd party utility, Delta3D, to manage our application. One thing that I'm going to try is to make a simple OSG application that basically duplicates our Delta3D scene and see if I have the same performance hit. I suspect that either Delta3D or our usage of Delta3D may be the problem due to the fact that osgviewer has little problems with performance when rendering our database. Of course, osgviewer only displays one model at a time, so that's why I think that building a simple OSG app might be a good test.
Thanks,Brian
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