Invisible City is a result of a workshop in The Master of Advanced Studies in CAAD at ETH in Zurich, not much information is given on this but it is probably a processing workshop that looks at generative processes in architecture/urbanism.
This particular work looks at a generative approach in city planning and it does seem really interesting to me.

Some information on CAAD, seems like a really interesting program if you ask me :
 
The Master of Advanced Studies in CAAD at ETH in Zurich is a one-year postgraduate program with a focus on computer-based architectural design and its automated production. MAS class this year is an interdisciplinary class of about 20 graduate students interested in research on the next level of Computer Aided Architectural Design. This class contains modules in theory, in basic skills about programming, and in the CNC production of architectural artifacts. The main interest of the research is the reflection on the potentiality of the upcoming technologies for future architecture. The class starts on an abstract theoretical and philosophical level and ends in exercises in designing concepts of future architecture on the so called symbolic level.

http://www.caad.arch.ethz.ch/blog/