How to make all baked objects have the same world scale? 

I have injected UVAtlas into our project to generate lightmap uv, and after I have generated them all, their uv almost have the range [0, 1), no matter how big they are. Then I can not assignment them into lightmaps according to their size.
I wanna know if there is a way in UVAtlas to make all baked objects have a same world scale.If not, I have to write a uv generation code I think.