This app could make many, many millions, if geared towards the real estate sector.
The desirability of the directions of the windows of any home, and its gardens, will depend upon its orientation to the sun. But shadows must also be considered. If someone loves the sun and its warmth, with the place facing sunward, but a huge tree or building is in the path of the sun, then he won't buy. But someone who prefers cool and shade may well buy. Any property can be sold upon its orientation to the sun and its surroundings, depending upon finding the right buyer.
Adding shadows will totally perfect the very best app I've ever come across!
Some simple real estate sales could hinge on the 2D model, while others upon the 3D. Why not charge the real estate agents for the more profitable 3D properties?