Okay so what is the preferred method for rendering with the intent to place the rendering over an image of the site? I took a high-res photo of the site today, basically just a field with some trees in the middle, and the building is going in front of the trees. I have a model of the building, with the intended parking lot and sidewalks as floor slabs in front of the building.
Now if I render with a background color, I believe I will have to erase around the model elements in photoshop. I also won't have anything reflecting in the windows. I also tried rendering with a background color other than white (like blue) and got a solid blue reflection on the windows. I tried rendering with a ground plane turned on, which gave me a more acceptable reflection in the windows, but I still think I will have to erase around the edges of the building image in photoshop.
Perhaps I should go ahead and model the ground as a floor slab and add some trees to get suitable reflections in the windows and just deal with erasing around the building in photoshop? Any suggestions would help.