Real time lighting. I cant get this to work?

For this environment i’m starting. i want to try going all real time lighting. i know …some how in unreal engine you can turn on some form of real time lighting? sorry, i dont know the exact name for this off hand but i believe it’s still not a full feature? i believe you can start using it now though yes? i cant find any sure fire method to get this to work correctly in unreal. i feel like there is some steps i’m missing?

Is it possible any UE master can teach me the steps, i’d really appreciate it.


What do you mean by real time lighting, do you mean realtime global illumination?

Like how cry-engine worked. I haven’t had to use unreal in a while. Some type of real time GI yes.

Realtime gi in unreal similar to what you have in cryengine isn’t possible yet.

I’ve seen people using real-time GI though? It’s called light propagation volumes or something? Can someone who knows what I’m talking about explain the steps to get this to work?

There’s LPV but it sucks, the alternative is Nvidia VXGI which isn’t going to work well enough on lower-end machines.

I’m trying to get into dynamic GI atm with a large outdoor scene.
I found this topic regarding LPV:

is this considered ‘suck’? or is this a very specific case.

UE4’s LPV implementation doesn’t support cascades so it’s not usable for large environments. With VXGI being too expensive and heightfieldGI broken there is unfortunately no option whatsoever for realtime GI in UE4 atm.

And in the meantime, Unity-Users are bathing in sweet warm GI water while we’re struggling (No offense, but they some nice GI cake, eh?)
At the moment, as an Level Artist i’m building quite advanced Asteroid Cavern Systems with sort of 1:1 scale (f* big). I am using some sort of fake-GI methods to enlighten rooms with movable dynamic lights and secondary lights to give these maps some “sort of” GI look while keeping all things dynamic. Baking lights is not an option for us since it takes too much time to bake. Occurring data is way too high for the number of maps we’re going to have and we’re looking into procedural generation as well. There’s not a single day i’m not watching at my glowing Ore materials and wish i could find an solution to enlighten the surrounding areas. Maybe, there might be some ideas we could collect to find ways to circumvent the need for GI by using existing features.

My current ideas:

  • Using an “negative” Ambient Occlusion on objects that features emissive materials.
    This AO method should work side by side with the regular AO, maybe through ID’s.
    It should take the color from emissive data and could be tweaked by radius and strength to lit up surrounding areas.
    Upside: Back in the days, i used this technique in offline post productions. Was not looking that bad at all.
    Downside: Just usable inside smaller areas, not sure about bigger ones. (Example: glowing stone on ground)

  • Fake GI light object
    Extends the regular light object by adding an spherical/box raytrace that “shoots” secondary lights into all directions. (~6 lights)
    The more one secondary light moves away from the initial light object the more it’s radius should grow and shrink its intensity at the same time.
    If one light hits a wall/ground, it just sticks to it. The secondary light should not have any reflection on other objects.
    Upside: At the moment i am using an similar technique. If i have an lamp object to light up a wall, i create a second light that is being used between the initial wall light and the dark wall on the other side to create some feeling of global illumination. It works in bigger rooms. Animation might be possible if raytrace is updating in realtime?
    Downside: Probably takes a lot of draw-calls? Secondary lights should not use shadows because of performance but may cast their light into other nearby rooms if there’s no math method to prevent it. (like shadows do)

I sure wish UE would get real time bounced lighting. it’s like the ONE thing i’m still waiting for. Volume fog is already done so, please add real time GI unreal team.

thanks for all the help btw.