Image-Based Lighting/Dynamic Irradiance Environment Maps?
Is it possible to do Environment Mapped Lighting as described in this paper from GPU Gems?
Real-Time Computation of Dynamic Irradiance Environment Maps
I'm a complete noob to UDK, so I wouldn't know it's capabilities. :/
You could create a skydome with the sky texture set to emissive and set to create lighting from emissive.
I think that UDK has some type of HDR import, but I haven't looked into it.
I'll have to try that, but what about Indoor + Dynamic Lighting?
You don't need image based lighting indoors.
I think there have been some people figuring out how to fake dynamic lighting with GI--there was someone who worked on an architectural thing of like a mall with a dynamic time of day, but I don't know how they did it.