One more thing about why we built it: The iPhone provided us an opportunity to experiment with a device that combines a 3d display with the ability to get real 3d input (not a mouse with the ctrl key). Goog 3dwh is a great data source and it made collada the natural choice.

The other developer here: in the current version, the client gets the data from google 3dwh and builds the gl model on the phone. We probably use >80% of the collada data in the google impl. The greater opportunity for time and space saving is in the texture scaling to iPhone appropriate sizes. Next release, we'll move that (and the XML parse while we're at it) to the server.