Our team is trying to develop a stealth system with the UDK. Part of this will involve lighting.
The idea being that if you're hiding in a dark corner of the room, the armed goons will not start attacking you.
I've been looking for a few hours now. And while I can't say I have no leads it seems that now is a good time to start asking for help.
At the simplest level, I'm looking for a way to determine how brightly lit an actor is (primarily the player right now).
A bit beyond that, what they are wearing might also be a factor. Someone wearing solid dark clothing is going to be harder to spot than someone in a loud Hawaiin t-shirt covered in (given the stealth context probably stolen) diamonds.
The lighting will be dynamic, so the solution needs to be dynamic. As an example, a guard might get rather upset, grab a torch on the wall and throw it in your direction.