Modelling a significant part of a city can be a very labour intensive process. VideoTrace simplifies the job of generating the geometry, as this video of the modelling of part of Copenhagen shows
Generating a model using VideoTrace assumes that you have video of the object which you want to mode, but makes the process of generating an accurate model, and the associated textures, a relatively simple process.
We’re currently working with the Australian Centre for Visual Technologies on a version of an Augmented Reality version of Videotrace that you can use while walking around. The idea is that you’d use a camera as a modelling tool. You would then walk around a city, modelling it as you go. Good progress is being made towards this goal, with a prototype system in the making.