This research spawned CityEngine from ESRI http://www.esri.com/software/cityengine and there are also a few more awesome papers from the same author, Pascal Muller, ex ETH and now at ESRI.
- http://www.eecs.berkeley.edu/~sequin/CS285/PAPERS/Parish_Mul...
- http://www.fdg2013.org/program/workshops/papers/PCG2013/pcg2...
- http://peterwonka.net/Publications/pdfs/2014.SG.Lipp.PushPul...
- http://www.cis.pku.edu.cn/faculty/vision/zeng/pdf/MullerZWG0...
See also Rome Reborn, a procedurally generated model of ancient Rome http://romereborn.frischerconsulting.com/