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Other than Quad-edge

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Hey all, I am wondering if Quad-edge http://en.wikipedia.org/wiki/Quad-edge, is a good method for storing and managing adjacency information for realtime rendering of terrain meshes? It seems like it would be effective but am unsure of other options, so please feel free to share any other data structures.

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Mesh structures with explicit adjacency information are mainly good for editing purposes of irregular meshes. Since explicit adjacency information consumes a lot of memory and terrains are usually large (and also static), one is normally endeavoured to use implicit adjacency information. A well known representation is the height field, where the values of just 1 dimension (namely the height) is stored explicitely, and the other 2 are computed on-the-fly at regular grid positions. The edges in-between are also only given implicitely.

So height fields are a very compact way of storing large terrains (or any other regular mesh), and hence can conveniently be stored in VRAM. That is todays way to speed up rendering to the limits. Of course, such height fields also have drawbacks. They e.g. don't allow steep slopes such easily.

In a word, first define the features of the terrain (is it static, is a LoD needed, is it continuous or tiled, how is it texture mapped, is irregularity a point, are steep slopes (or even "holes") of interest, ...) and then decide on the structure.

EDIT: Err, I read a bit furthur on Quad-Edge and saw "polyhedron", "manifold", "closed regular" and so on. That doesn't match fine with terrain, does it? But perhaps extended usages exist as well. But that would otherwise increase the effort even more, I think.

[Edited by - haegarr on May 17, 2008 4:31:17 AM]

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