Procedural Architecture /was the focus of my final project for my masters degree in Games Programming at the University of Hull. I developed some software which procedurally generated indoor architecture. I called the program Picag. The inspiration for this was games which have large city environments like Grand Theft Auto 3 or Driver. The buildings in these games are just external walls - you can't go in any of them. So my idea was to procedurally generate simple interiors like apartments and shops, based only on the external shape of a building.
As it stands, Picag lets the user draw an outline building shape in two dimensions. Then, in three dimensions, you can step through and watch the algorithm laying out a floor plan within this shape and turning this into walls, doorways, and windows.
I had plenty of good intentions to add stairwells, lifts, corridors and decorations, but only three months to research and implement the project. After developing this, I concluded that procedurally generated building interiors is probably acheivable for AAA games, provided you have an extensive and reliable geometry code library to build on.
My dissertation on this is about ten thousand words. It included research into existing forms of procedural architecture generation, my initial design for the project, details about the implementation and key algorithms I used.