Holophone3D is a virtual 'hologram' app for Windows Phone that lets you explore 3D graphics and play a number of 3D mini-games. It's a very clever implementation and a great example of the potential graphical prowess of the modern smartphone. The latest update, version 1.8, adds a HoloSketch module that lets you turn 2D drawings into 3D and a new stereoscopic renderer for all 'holograms'.

Holophone3D has two ways of creating a 3D effect. One is using a standard stereoscopic implementation, that requires 3D glasses in order to view the 3D effect.

The second is a rendering effect, which the developer describes as being like a 3D hologram, in which objects appear to project out of the back of the screen. It works best if you look directly down on the phone from above and close one eye. The 3D effect becomes more apparent when you pivot the phone and also works better in dim light. It's really rather impressive and makes for a great demo to family and friends.

The 3D effects can be seen in the content that is built into the app and the app's interface itself. The content includes scenes and a number of interactive objects and models. With the interactive content ceratin objects can be moved around in a 3D environments with realistic physics effects and lighting and shadow effects (powered by the SunBurn engine). 

Holophone3D also includes a number of mini-games, which might be described as interactive holograms. These provide an additional showcase for the app's 'hologram' technology. There's a 10 level marble maze game, an asteroid attack game, and HoloSketch. HoloSketch, the latest addition, allows you create your own 3D drawings. The drawing is done in 2D, but there's also a depth control element. Thus when you switch on 3D mode you see a layered 3D version of your drawing. The pictures created using HoloSketch can be saved and then shared with our friends via email or social networks.

Here's a video that demonstrates the HoloSketch feature and also touches on some of the apps other functions.

Holophone 3D, is a very impressive example of what can be achieved using Windows Phone's XNA graphics technology. The app can mainly be considered a technology demonstrator, although the mini-games do provide some lasting value, but ultimately it is the wow effect of the 3D 'holograms' that provide the main reason to download the app.  

A trial version of Holophone 3D is available from the Windows Phone Marketplace. The full version, which adds additional content and enables the HoloSketch mode, costs £0.79 / €0.99 / $0.99. 

If you are interested in reading more about the background behind Holophone3D works you may wish to visit the developer's website, which includes a page detailing the history of the app and a blog that describes the latest updates to the app.