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=3D Models=
 
=3D Models=
Contrary to what many people believe, the impact of high vertex-count models on framerate is fairly minimal. For graphic artists, the key things that should be avoided are:
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Contrary to what many people believe, the impact of high vertex-count models on framerate is fairly minimal. In addition, for graphics hardware built after 2004 and intended for games (example: Nvidia GeForce 6 series), textures are close to, or completely, free. Today (in 2010), the major graphics bottleneck is between the CPU and the GPU. The goal in optimizing models is to store as much as possible on the GPU and reduce the number of rendering commands sent to the GPU. For graphic artists, the key things to remember are:
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* high resolution textures
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* Reduce the number of different textures used on a model to a minimum. It's better to use a few (or one!) big textures than many little ones.
* textures containing alpha
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* Avoid mixing textured and untextured geometry in the same model. Build the coloring into the texture map instead.
* textures themselves
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* Within your modeling tool, try work with large meshes instead of groups of small meshes. I know that this can result in a very unpleasant workflow; we are working on optimizations in Flightgear that will combine mesh parts automatically.
* unwant polygons casting shadows
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* Textures containing alpha cause various problems. In order to be rendered correctly, translucent geometry must be sorted by distance on the CPU. Furthermore, geometry is sorted on a course level (basically by mesh), so you may see various artifacts. If you have some transparent parts of a model,
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you should violate the first rule above and assign those parts to their own texture.
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* Don't assign an RGBA texture to a model that is completely opaque!
    
=AI traffic=
 
=AI traffic=
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