Dark-to-lit room static lighting transition - how ?

The idea is to have two lighting states for a level (or even individual rooms) - dark and lit. Is it possible to bake 2 different static lighting schemes and then blend between them (or fake it somehow) ?

Here is a scenario - player enters dark room, flips switch, room lits up. Dark room lightmaps blend into lit room lightmaps.

How do I go about changing static lighting (pre-baked) in runtime ?


Without modifying the engine, it is unlikely.

Potentially, you could just make two versions of the same room as two different levels, and load dark or lit level depending on the switch position.

How would I “blend” between 2 (streaming?) levels ?

You can change the brightness of stationary lights after baking, but you can only have up to 4 over lapping. Also turning brightness to 0 cause some artifacts, but you could probably hide it with some post processing, emissive parts on materials to distract, and/or having a few point lights that are very low intensity.

I am working with mobile VR, so post processing is out of question.

Stationary lights are utterly broken in UE4. In some cases they cast baked shadows, in some they do not (in my basic test project using FPS template I get baked shadows from Stationary lights; in my actual project with my own static meshes, they don’t cast any kind of shadows).

So basically I am only limited to static lights and baked lighting.

You wont be able to blend smoothly between them.