normals and rotations

Hi,

short question:

If I have a normal in a certain vertex, and then rotate the vertex, do I have to rotate the normal too??
I mean physically rotate it in 3D-space with sin and so on. Like rotating around Z-Axis 90°. From my point of view I don’t have to rotate the normal since it is situated perpendicular to a vertex, right??

I’m a little confused about this topic since the last discussion with a colleague.

Thanks,

Martin

The normal should be rotated with the object. If you rotate your object with OpenGL’s own matrix functions, the normal will automatically be rotated.

Thanks Bob for solving this mysterie!

Martin