Humus has released a new Direct3D demo. Interior mapping is a technique that renders the interior of buildings without requiring additional geometry. Everything is done in the pixel shader. The advantage is that when you’re rendering large cities you can draw all those buildings as simple boxes. This demo requires DirectX 10.1 and Windows Vista SP1.
Source Code and binaries: Interior Mapping Demo
Update – 2008.08.17
Demo has been updated with around 80% of performance boost.