please *explain* reflection

I’ve seen several tutorials which explain how to make a plane reflective (by placing an empty below the plane, etc., etc.), but I have no idea why this works. I would really like to know why this works, because I would like to make other shapes reflective, and I can’t do this because I don’t understand the underlying principles. Can anyone really explain what’s going on with this empty and choosing an object for the reflective texture, etc. Thanks for any response.

https://blenderartists.org/forum/viewtopic.php?t=16948 <-- best I can do. hope it helps.

Basicly, the Empty represent the point of view of the reflection. For a curved surface, that’s easy to visualize, since it represents the focal center of the mirror. For a planar surface, it represents the position of the camera reflected by the mirror. That’s why planar reflection will look slightly skewed.
Example:
http://www.clubinfo.bdeb.qc.ca/~theeth/Temp/Reflection.png

Martin

Thanks for your responses. After your help and a little more thinking about it, I think I have it. Thanks again.