Mirror modifier doesnt work.

I wanted to model a face in the way J. Williamson did it. However mirror modifier doesnt work on a plane on my version ( 2.45) but works on the cube. HELP! PLEASE! I havent tested if it works on anything besides the cube tho. I really need it to work on the plane to do the face right.

The mirror modifier works on any shape Blender is capable of producing. Sometimes, if you mirror on the “wrong” axis, you won’t see anything, because the mirror copy is lying on top of the original mesh. Try moving the mesh (in edit mode) off to the side a bit before turning on the mirror modifier. You’ll see what I mean.