You work with 3D on a city level that has developed a lot during the last years. A first project was sketched by by Lærke and Mads in 2012. The city of Copenhagen has implemented it in a real data platform, amongst showing the solar potential for the buildings in Copenhagen and a open data service at http://kbhkort.kk.dk.
If you go further and enter the buildings, Google did a good job – See the Google Indoor “Maps” solution that has different names “Plan” “Indoor maps” … https://www.google.com/maps/about/partners/indoormaps/.
The interest for further implementations of the ideas is broad. We are looking for students to follow up including BIM, GIS and other technologies, visualizations and app implementations.
You can also get inspiration from the solarvision project (Visualisation from this site).
Interested? Contact me – (Al)Fred Heller, DTU.