Model your house in 3D

Posted on 7 Dec 2007 at 11:27

Google Earth's use of satellite and aerial imagery is very impressive, but the fact that the program isn't limited to top-down views is even more extraordinary. Using the Tilt control at the top-right of the screen you can angle your view and enter a 3D representation of the scene. Thanks to built-in altitude data, you can fly through the Grand Canyon, say, or climb Ben Nevis. All of which is great for natural landscapes, but what about manmade cityscapes? To give these experiences similar immersive depth, Google Earth needs to be able to handle buildings in the same way.

And it can. When Google acquired Keyhole Inc and its Earth Viewer back in 2004, it also acquired its Keyhole Markup Language (KML). As we noted earlier, KML can be used to denote placemarks, but it can also describe 3D data and even 3D models, so long as they're kept simple.

KML is an open language and so potentially any 3D application can output to it. However, there was one application that could have been tailor-made for the job. SketchUp (www.sketchup.com) from @Last Software had built up a loyal following, primarily among architects, thanks to its pioneering approach to 3D. As its name suggests, SketchUp is designed to make 3D modelling as simple as 2D sketching. In particular, rather than creating smooth organic models from complex polygonal meshes, SketchUp is designed to produce more "boxy" architectural models built of comparatively large flat surfaces.

SketchUp is a natural KML modeller and when @Last Software added plug-ins to enable its models to be loaded into Google Earth, Google liked what it saw so much that it bought the company - and promptly launched Google SketchUp for free. It wasn't an altruistic act: Google can't possibly model every building of interest, but end users can and will "model the world", as the new SketchUp slogan puts it. Google will recoup its investment many times over via the advertising opportunities such rich content creates, as well as from selling the commercial SketchUp Pro, which exports to 3D formats other than KML.

Buying Keyhole and @Last were excellent moves for Google; and getting Google Earth and SketchUp for free is an unbelievable deal for the end user. Two years ago, could you have imagined you'd be working with a ground-breaking 3D application to create instantly and universally accessible models ready for incorporation into a state-of-the-art geo-browser? As the walkthrough below shows, such bleeding-edge technology isn't only possible, it's actually quite simple.

Before you get started, there are a few guiding principles when creating a building for Google Earth. KML's rudimentary 3D handling and the demands of web-based delivery mean it's best to keep the model simple and the file size small. Large flat surfaces are key, so start off thinking in terms of a simple box rather than the Sydney Opera House. If your planned model is inherently more complicated, make sure that any repeating elements, such as the pillars in the Acropolis, are efficiently handled as referenced components. Alternatively, you can take advantage of Google Earth's recently added support for bitmap textures to instantly bring those flat surfaces to detailed life.

Google SketchUp lets you distort images to correct for perspective, but it's better to have head-on photos for each of the major planes in your model. You'll also need a basic photo editor to crop, resize and compress your JPEGs to keep download size to a minimum. If you don't already have one, just add the excellent Picasa to your collection of outstanding free Google tools.