I made a small tutorial or demonstration, what ever this is.. A small project that shows what the different shaders do, how mipmaps work, some basic LOD stuff and two corners with correct and incorrect panel lengths, a common problem i've encountered almost on every betatests I've done for folks.
Download the project: http://cream.galleria.fi/BTB/Tutorials/MipMaptutorial.zip
Export to your game of choice.
When you drive on the track, you'll see some walls that are bent at the top. There's six lines of them, the order from left:
Diffuse, Diffuse+Bump, Diffuse+Spec, Diffuse+bump+spec, Diffuse+bump+spec without mipmaps on diffuse texture and finally simple Diffuse with no MipMaps.
Look at the objects at different angles, drive or use freeflight cam, replay what ever works.. The diffuse texture has a single color section in the far left, there you can see what bump and spec maps actually do. You can browse thru them in BTB material editor later. Or now would be a good time.
Drive on track. First corner has correct panel lengths switching to incorrect length. Further on the road you'll see the texture getting blurrier. That's the difference between mipmap bias -4 and 0. Stop there so you can see the change and try different cameras to see what is the reason for all of this mipmapping stuff. In the last corner there's a example of totally wrong mipmap level, the material uses +4, all the details are gone. Test different cameras, some detail may be visible from free flight cam…
The six lines of objects uses -2 mipmap bias. Use BTB material editor to edit mipmap biases, export and see what the difference is. You should also check the diffuse, bump and spec maps, they all have "flat" i.e. single color sections to show different points. You're job is to figure it out..
The trees use 50 and 75 LOD, the track should be longer to really show the effect but at least i got one jumping tree there..
So this a DIY tutorial, experiment with it. Try to find a good mipmap bias for the last corner. Edit the walls and road to correct panel lengths. For LOD tutorial i made too tiny track, there is one jumping tree, i don't know how to fix that, BTW.. I'll upload the original textures used in the tutorial as a bonus, it's pretty usable plastered cement texture with good bump and spec maps. DL: http://Cream.Galleria.fi/BTB/Tutorials