We were surprised when non-CAD-vendor Google bought SketchUp, but then learned they wanted it to populate Map and Earth with 3D buildings, first as simple extrusions and then with bitmaps pasted on the sides. The problem was that it involved manual labour and so coverage was spotty.
We were then even more surprised when Google sold SketchUp to Trimble, known more for professional GPS systems than for CAD software. Today, we learned why: Google no longer needs SketchUp for its intended purpose.
Instead, Google is using a new technology to automatically generate 3D buildings from 45-degree angle aerial photography made by overlapping passes of aircraft. Each airplane has five cameras: four that point at 45 degrees, and one that points down. Then the data is processed:
1. The aerial photos are combined to create 3D models.