Occlusion Culling Problem

[Dave]

I am currently using Soliddesigner/Annotation version 9.1.0.15 on a Pentium 3 600 with Windows NT 4. I recently had an nVidia Quadro4 550 XGL video card (64 MG of memory) installed which claims to have second generation Occlusion Culling capability. When I try to enable the Occlusion Culling function from Soliddesigner under the Tools/Graphic Settings command, it is grayed out not allowing me to select it. Does anyone know why the Occlusion Culling will not work as advertised? I have contacted CoCreate and nVidia but they haven't been able to help me.

[Claus Brod]

Dave,<p> <p>I can confirm what you found. The 550 XGL doesn't seem to provide any of the flavors of occlusion culling which OSD requires. I will add a note on the external graphics card page on our web site, and also contact Nvidia to find out more about it. Sorry for the confusion, and thanks for raising the issue.</p> Claus

[Jeff]

So does the 550 XGL have occlusion culling but just not the right occlusion culling to work with SolidDesigner, or does it not have any occlusion culling at all. NVidia lists "2nd Generation occlusion culling" in their key features.

[jeff]

I see that the Quadro4 700/750/900 XGL are still listed under the "certified graphics cards" as supporting occlusion culling. Do these cards truly work while the 550 does not?

[Claus Brod]

Jeff &amp; Dave, <p>I have contacted Nvidia to find out precise details on the status of their occlusion culling implementation in the various Quadro 4 versions. During our earlier tests, we found occlusion culling to be working in the 700/750/900 XGL cards, but we will re-run our tests now in order to see if there are driver dependencies which might hide that feature from the application again.</p> <p>While probably all the recent Nvidia cards and chipsets perform some amount of occlusion culling <em>internally</em>, not all of them expose the associated OpenGL extension API to applications through the driver. This OpenGL extension API is what OSD is checking for when it starts up; if it is available, it will make use of it in several functionality areas. The most important of those areas is 2D drawing generation for large assemblies, where using the extension API can speed up the computational tasks tremendously.</p> <p>Again, we're in touch with our partners Nvidia and try to clarify the issue. We will also re-run internal tests to double-check our earlier results.</p> <p>Sorry for the confusion,</p> Claus

[Claus Brod]

Dave &amp; Jeff, <p>I now have a definitive answer from Nvidia. The Quadro 4 550 XGL indeed does not support the occlusion culling APIs which OSD requires for advanced performance features such as Econofast. The other cards, however, provide that support.</p> Hope this helps,<p> Claus