I manage to do this by re-importing.

Thank you @hansmex

I tried several times to resize every level but i never succeed because there are some walls appear in both levels.

Is there any tool to resize obj file ?

Hi
I want to resize the whole building with every furniture in it.

I used Advanced Editing plug-in but i have 3 levels and I don't know how to select them all!

I've tried to Ctrl + A but this select the current level only.

Any help