Creating and Using Normal Maps
In the last 10 years or so we�ve seen lots of video games released that use low poly count models for the game play and then tell the story using pre-rendered cinematic sequences. The characters in the cinematics always look really nice with lots of detail and realism, but as soon as the game play starts again, the model is back to being low poly and very chunky looking. Wouldn�t it be cool if you could make your 1500 poly real-time model look like your 2 million poly cinematic (software rendered) model? That is the main goal of using normal maps. The idea is that you take all of the detail from the high poly model and put it in a normal map. Then you apply the normal map to the low res model just like you would add a texture map. Now you have a low res model that looks a lot like the high res one. It�s not perfect, but it�s a pretty good trick that makes low res models look A LOT better than they have before. The aim of this tutorial is to introduce you to creating normal maps and help you understand the principles involved. Because normal mapping is a bit technical in its approach, I want to explain it in such a way as to allow game artists without a lot of technical background to understand the technique and be able to use it.