The process of making 3D models of real-life buildings that will appear in Google Earth is called geo-modeling.
Choosing a geo-modeling method:
Geo-modeling with Building Maker
Google Building Maker is an online application specifically for geo-modeling. If the buildings you want to model are located in an area where Building Maker imagery is available, you should choose this method.
Learn more about geo-modeling with Building Maker »
Geo-modeling with SketchUp
SketchUp is a tool you can use to build 3D models of anything you like – including buildings for Google Earth. You should use SketchUp for geo-modeling if you can't use Building Maker (see above), or if the buildings you want to model are very complex or unusual.
Learn more about geo-modeling with SketchUp »