This is a plugin I wrote for Goldtooth Creative back in the end of 2010. (Thanks to Goldtooth for allowing me to post this). It was used in the game Deus Ex: Human Revolution to render the shadows in all the cut scenes.
The plugin is a modification of the Maya Cgfx plugin, which I enhanced to:
The plugin allows artists to see shadows in all viewports as they work. Since SSAO requires fremebuffering, it can only be seen in a specially constructed viewport.
Here is a video of a Maya session with shadowed lights in a regular Maya viewport:
This shows two renderings of the same geometry side by side. The first shows the SSAO buffer alone, the second shows it composited into the scene:
Here are some renderings of a room I created. In these, shadows are disabled so that the SSAO is more apparent:
And the same room with shadows and colored lights: