What is a normalmap?

[Kernel39]

This is a noob question, but what exactly is a normalmap and what does it do?

[Shocky]

You can always type on Google "Normal Map" and it will show you what that is, for example check the wikipedia link here or here or here or here and there are even more you can find on the first page on google explaining what that is.

 

"A normal map is a way of adding high-resolution detail to a game ready (low resolution) model, without drastically affecting the game's performance"

[Serithi]

A normal map is basically a way to add little details (bumps, scratches, etc.) that catch the light and appear as if they really are little changes in the shape, without actually adding those details to the mesh itself which can take some serious detailing work to get right.

 

For example, pores on a skin texture. It looks for all the world like they're really there in the skin, the subtle dips and bumps as you move the view around, the lighting hits is as if they're there, but it's ultimately actually just a 2D texture and the mesh underneath is basically flat.