Do you think WoW is using LOD?

Yes, they definitely use LOD. If memory serves it's a configuration option.

See "Level Of Detail" checkbox?

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Original post by ShaneeWhat kind of LOD algorithm do you think they use if they do?

They use different mesh for distant (fog only) terrain, probably some PM-ed terrain. Near-by terrain is patch-based, where patches are ROAM-optimized and their LOD is discrete - kinda visible popups all over the place.
Objects don't use LOD afaik, at least in the first expansions.
However in the last expansion they have increased their budgets quite a bit, the game sometimes shows scenes with tons of objects + detailed terrain for like 30 fps on my 260.
Characters fade quickly to use any LOD, so I think there is none for them.

I am trying to decide which LoD algorithm to used, so far I am thinking of Chunked LoD

I'm fairly sure it's an extremely simple chunked LOD, I don't think there's any ROAMing going on.

I think the WOW terrain works with hexagons rather than squares.

There are many tools that can load up the terrains of WoW and there are tools that can turn the WoW game into wireframe mode.

There used to be LoD for terrain but with a modern discrete GPU, it is faster to turn off LoD and allow it to use brute force to render in the highest detail.

From the wire frame mode, you can find the terrain is triangle (square) based.

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Original post by pcwlaibut with a modern discrete GPU, it is faster to turn off LoD and allow it to use brute force to render in the highest detail.

Did you made any tests?

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Original post by Zemedelec Quote: Original post by pcwlaibut with a modern discrete GPU, it is faster to turn off LoD and allow it to use brute force to render in the highest detail. Did you made any tests?

I played WoW from the very beginning after it launched. At that time, I was using:

Intel Pentium 4 2.4Gz + 1GB RAM + Radeon 9800 Pro.

When turns on the LoD, the performance is at around 1x FPS. When LoD is off, it can climb to 4x FPS.

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Objects don't use LOD afaik

The environment detail slider has an effect on object level of detail (it changes the distance at which their LOD changes)

I suspect it uses a very well implemented octree system of course (interiors seem to have a more specialised occlusion system that ties into the exterior octree)

It probably has a cheap way of lowering the detail of very distant terrain, though mountain tops seem to be cleverly marked to remain high detail at long distances. Blocks of terrain may also be culled by the far clipping plane on a pre-draw call level. But all that is quite close to just brute forcing the terrain.

Does anyone know if wow uses antiportals to cull areas of the octree? I think they may be one of the ways some interiors are handled, but also involving intelligent level streaming at the same time.

For the terrain mesh part, it is not rendering a lot of polygons in each view. Also, the distant terrain mesh even with high detail, only rendered with plain color with fog enabled. This helps to keep the GPU working hard on filling with single color which is easy and efficient. You can have a try and test it for yourself.

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Original post by pcwlai For the terrain mesh part, it is not rendering a lot of polygons in each view. Also, the distant terrain mesh even with high detail, only rendered with plain color with fog enabled. This helps to keep the GPU working hard on filling with single color which is easy and efficient. You can have a try and test it for yourself.

Distant mesh is very optimized and is projected directly into [FarZ,FarZ] range. Thus Z range is not very big, compared to the visible distance.