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zhangjiq1983

About terrain PVS......

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Hi all, Our game have realy large outdoor terrains,and we use some simple LOD and quadtree to minimize the triangles have to draw. The problem is I just can't cull off the patches behind the hills. I found this terrain PVS tech , and I think it can help to do this. http://www.gamedev.net/reference/articles/article1936.asp The only problem is this tech can't cull models but just terrain patches. I want to know if there is any other good ideas can handle this?? Hope I made myself understood... Thanks for all.

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Could you 'link' models to a terrain patch, so that if the patch is culled, the model is also culled? This would probably cause some errors though, seeing as the models might be quite a bit higher than the actual patch...

Gamasutra has an article on using 'occluders' for outdoor rendering.
AFAIK Valve's Source engine uses a technique like this for their outdoor rendering - what they do is put a large occluder-volume inside large hills. This way all the models behind the hill will be in the "shadow" of the occluder-volume (i.e. the occlusion frustum), and will be culled.

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Have you looked into occlusion culling? Not sure what graphics API you are using but occlusion predicates in DX10 are great, but regular occlusion queries work too. Rendering the terrain first, and then doing occlusion tests on the bounding volumes of your other meshes should work.

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Thans for the reply.
The method of putting plane inside terrains sounds applicable, and it just some jobs can be done in the editor, I may try it later.

Our game use d3d9 based on renderware3.7, so d3d10 is just not the case.

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