Hi,

Am new to houdini and am trying to figure out a way to use it in my modeling workflow.

The concept as follows:
1- import building footprints as lines
2- Apply a digital asset that generate buildings to each footprint separately and randomize the parameters.

I've tried to do simple extrusion of the polygons but all follow the same height.

http://forums.odforce.net/topic/24808-random-extrude-distance/ [forums.odforce.net]

After you become a bit more familiar with Houdini and you want to do something more involved like taking existing city/municipal datasets the following videos might give you some ideas of steps to take:

http://www.entagma.com/quicktip-visualizing-flight-paths/ [www.entagma.com]
http://www.entagma.com/niklas-rosenstein-python-in-houdini-visualizing-satellite-data/ [www.entagma.com]
https://www.sidefx.com/tutorials/houdini-16-masterclass-heightfields/ [www.sidefx.com]