Why use normal maps?

I can do the same thing with a normal map in blender game engine with just using the picture. I can just keep color and checked and check geometry and I get the same effect as using a normal map. I just wanna know why people use normal maps?

Well, if you do it right, you can turn the model on the left into the one on the right. Of course, a specularity map is also probably used in these pictures, but the fact still stands.

oh ok that looks pretty cool

Iv found that using the geometry setting to create normals works better for renders than it does for say a game object. Plus setting the normals with geometry wont yield as good results as a separate normal map would from what iv seen in the past.

Normal map will in a way give the appearance of more complex geometry then actually exists. It’s (not but in sort-of way) a games engine form of sub-surf (an apples to oranges comparison mind you).

Yeah, the other Geometry settings (?) don’t work in-game - only the Normal setting works in-game.