by IrascibleOne » September 22nd, 2011, 11:49 pm
I think you do have to name it right, if I remember correctly.
From what I have read, things on the right would end in an R and on the left they should end in L. I think I've seen both the ".R" and "_R" format used before. When you mirror it, Blender should automatically give the new side the same name, but change that last letter so you can easily tell left from right. For instance, Hand.R when mirrored should automatically name the left hand Hand.L.