# What exactly does the Normal node do?

The Blender manual page doesn't give too much information. It has a sphere to change a direction. What direction does it change exactly? I understand that normals are vectors perpendicular to mesh faces, but I just can't figure out how normals work inside the node editor. When I rotate the Normal node sphere, is it changing normal DIRECTIONS? How do I predict the result? I'm so baffled by this.

Thanks.

The Normal node outputs a normalized vector ((X,Y,Z)), meaning a vector with a length of 1. The ball represents the direction of the normal, like you were looking down on it from the top of the 3D Viewport.
Therefore, the default output of the Normal node is (0,0,1), or directly up. When you rotate the ball, you are changing the output normal, as if you were looking at it from the top, so +X is to the right, and +Y is towards the top of your screen.