Keynote Reference Guide

[Verdite]

I think Airflames is right on this one... Though outside of motion mode all you need to is select the whole model, then hit selected - mirror - whichever axis you need. What i do is i move the model slightly outwards from the y axis... And mirror then. If i want to move this mirrored piece, i select it, copy it, then delete and paste it as a new obj. If i want to make sure all the faces join perfectly, keep the two parts slightly apart, select with the rectangle down the centre of both, then use "scale" to bring the two parts together. If the models a bit distorted i select all and scale until its right.