A university project I did for my MSc Computer Animation and Visual Effects degree in Bournemouth University.
Houdini Procedural City:
The HDA was developed in Houdini 11. It support two methods, Grid and Voronoi. Both give different distribution results.
The HDA supports up to five assets by default but can be extended to support as many the user wants.
Also the HDA was developed with speed in mind, so that the end-user can view the changes real time with minimal data cooking.
The procedural city engine is based on color instancing and clustering. Each color corresponds to a different geometry but it is possible to group similar colors as a cluster for a more cohesive look.