When discussing the new Ovi Maps 3D a few days ago, one interesting point about their maps are how they are generated — hundreds of aerial photographs, automatically converted to 3D.
It’s apparently growing into a popular technique, as Pix4D is showing off some similar technologies.
In the article they mention using the Swinglet CAM as a great way to capture the imagery for uses like this. The “4D” part of the equation is time; you can view the progress of 3D buildings through time, assuming you’ve done enough captures of a particular area.
It’s a great concept, and yet another way to generate 3D models. As all of these techniques continue to evolve, I expect we’ll see an even more rapid expansion of 3D models in Google Earth.