Irregular surface.

Hello,

So for my project I am given a topo (which means it is a very irregular surface) and houses on it. So what I am trying to do now is to slide the UV slider and for whatever building or brep is selected to morph into a geometry.

1. I am having trouble with the surface normal now. For the parts where the surface normal is up the geometry is pointing up but at the parts where the surface normal is down, the geometry is pointing the wrong way.

2. The geometry I have made is a house so is there anyway I can make it face the street?

3. I am also interested in having the geometry be different at different heights on the surface. So any suggestions or hints?

-Thank you so much. =)