Could you elaborate?
Do you mean you go to the site of the proposed building with a tablet or smartphone, run BIMx on it, point your device so it shows the site and BIMx shows the proposed building in the context of the real world?
Or something different?
One of the aspects covered by augmented reality yes is this, to show the building in the site from far distances, probably with the use of gps.
But augmented reality can be used inside the building too. how about to be able to isolate selected object/s (with xray view would be nice) and align with the space-zone you are in? eg isolate furniture and show walls in xray, then align and start moving around to see how thinks blend. Or show MEP inside walls.
Also very impressive would be to align the drawings with the real world.
The difficult think is not to show a camera view against the bimx content, but to align with each other and keep like that, while moving around the building.