Accurate shadows for AR?

I am having the hardest time getting shadows to be cast onto nearby objects like groundplanes or different surfaces. I just can’t get it to work and I do not know what I’m doing wrong.

All I am getting are the soft, round faked contact shadows that are spawned in with the placeable blueprints we’ve created.

What we want is a small city scape, a couple of buildings and a ground plane and have shadows projected so you can see how light would land on nearby buildings if you were to change something in the cityscape. But right now all we have are the very rudimentary self-shadow/direction indicating shadows that are just displayed based on angles.

Can anyone provide any help with this? We are developing for Android atm.