Q: You're building Thief 3 around Epic's Unreal technology. In what ways is this enhancing the gameplay experience?

Smith: One of the biggest differences for Thief 3 is that it uses state-of-the-art rendering technology. We've got fully volumetric shadows, which other companies are using now; but as early as two months ago the only companies we knew that were using this were us and id Software.

We try to use the rendering technology for gameplay all the time, so in a room, say, you might have an oven that's casting light. So the fact that any object casts a shadow from any light source means that the player has a lot more control over lighting in Thief 3.

You're allowed to put out torches, for example, to control the environment. Or if light is streaming through a window you can push a piece of furniture in front of the window to block light.

Also we have stuff like guards carrying torches. With the new lighting system... before you could just hide in shadows indefinitely but guards can now bring light sources towards you. You could use water to put out the torch but that makes guards suspicious and so on.

And we've got rag-doll physics so enemies realistically collapse, and they conform to the terrain beneath them, which is pretty cool.

In general the game looks good and plays well - it's got a really high production quality.