Put simply, LODs are the way your viewer interprets an object's detail as the camera gets further away. When uploading a mesh model, you can control the amount of detail at each level.
When uploading a mesh in SecondLife, you will see a screen similar to below. This is where you can adjust your model's level of detail at different distances.
Below is an example of how an object's quality changes as the camera moves further away. The further away you are from the object, the less detail it is required to have.
How to configure LOD
The mesh uploader automatically generates LODs suitable for a basic import, though often these should be changed to achieve a better detail/land impact ratio. The higher the LODs, the higher the land impact.
A general guideline for the LOD scales is to reduce the triangle count by 50%-75% at each level. For example, if the most detailed model is 4000 triangles, the next level should be no higher than 2000 triangles. The next level should be no higher than 1000, and the lowest should be near or below 500 triangles.
Tip: Use the mesh uploader's preview to see what your mesh will look like at the different levels.
