ya i created one side of the face but when i duplicate it to other

side it comes out black so i was messing with maya and i found mirror geomtry and used it

it worked the other side came up right

so now my question is miror geometry different from duplicate

ex: if i set the UV's for one side and used mirror geomtry

instead of duplicate (because duplicate not working as mentioned before) will the texturing work the same as when iwas using duplicate

if not then i need to fix the problem with duplicate

i know this sounds wierd but plz help thanks