Dave, I think the problem is when I use this method it doesn't mirror them as two seperate objects. I can't just select one side without selecting the other, even though I unlicked "merge with original" in the settings box.Use the mirror tool in the mesh menu, if you model is in +x you need to mirror in the -x.............dave
Thank you Stwert. I did this and it worked.I don't believe the mirror geometry tool creates an instance, which is what you'd need to have the shape update. Try setting the pivot point to the origin, then enter -1 in the X scale in the duplicate special options. Right now there's no change in transform (i.e. rotate and translate are 0 and scale is 1) so there won't be any change in position.