Google had a stroke of genius when it purchased Sketchup and made it freely available. It suddenly opens up basic Computer Aided Design to the masses and with it the tools to model urban areas. If you run a simple search on London in the Google 3D Warehouse it become clear that something has started – people from all over the world are now modelling cities.
What is needed is simple to use tools so you don’t need mapping data or on site surveys, all you need is a digital camera. To this end Sketchup has come up trumps with the ability to push and pull images onto a face and recipe them. Sure its basic and the accuracy of your heights will be out but as a guide its a great way to push and pull buildings into shape rapidly.