I'm currently writing an article (for the MTBS bonanza contest!) but I want it to be as accurate as possible while describing in an easy to understand manner the definition of "2D plus Depth".
Here is what I have so far, and it applies to gaming (I know 2D plus depth/3D conversions are probably done a bit differently in film):
[2d plus depth] is where, to save on the processing power required to render out two separate images for the left and right eye, the game renders out one image, then overlays that image on to depth data generated from the 3D geometry in the scene. Some computer trickery is then applied in order to try and fill in the information that is missing from the second image that the left eye could see but the right eye couldn’t (the background behind an object close to the screen for example).
Is this roughly correct?