Apply symetry on a model with multiple elements

[Anonymous]

Hi everyone I got a question. Well, using symetry when your model is a single element is easy, but I don't know how to properly apply the symmetry modifier on it when the model has multiples elements.

Let me explain, I'm modelling a building:

Now I need to apply a symmetry to it, but as you can it it's comprised of more than one element: The fissure between the building'floors, the roof and some other, and their pivot do not share the same position.

And I don't want to attach the elements, because I will unwrap them later, and I need to keep it modular. 

 Is the only way symmetry each element at a time? Is there a way to, at least temporaly, make the pivot point oh each element to be at the same position for a proper symmetry operation?

Thanks in advance!

Thanks in advance.

[Anonymous]

Rather than using the Symetry modifier, have you tried selecting all the objects, then using Mirror, from the main toolbar?

[Anonymous]

I would get messy results anyway, because the mirror tool would use the pivot points to work...

[Anonymous]

If you select all the objects together and apply the symetry, they should all get an instanced modifier with a common mirror origin.