Pappenheimer... I understand how to set the movement restriction, but "switching the normals of the mirrored part" is confusing me. I'm not sure how to do that? (I checked the online manual to see if it discussed this, but couldn't find it.) I just did a really simple test of taking a sphere, cutting it in half, copying it, pasting and then mirroring the pasted copy. After this I moved it out to the right a little. The outside of the mirrored sphere is dark grey in the gourad shaded preview (with draw backfaces checked) and the inside is light grey. It is the opposite on the original. When I uncheck draw backfaces and rotate the camera around behind the mirrored half sphere I can see a hole through it. When I rotate around the original I don't. I probably won't use this to model heads (looking at Blender), but I would like to understand how to use this mirroring function correctly in case I need it. Thanks for the help.

Thanks, 3dworld... I am trying to study Blender to see what I can accomplish with it.