What are my options for point light dynamic GI?

In my level, I would like to use GI and allow the player to turn lights on/off in rooms. All of the methods I’ve come across for dynamic GI do not work for point lights. Does anyone have any ideas on how I could get around this issue?

Dynamic and (good/realistic) G.I don’t go in the same sentence unfortunately.

You can have a baked lighting with good G.I and some toggable point lights here and there, but toggable point lights alone won’t give you a nice G.I
Unless I’m missing something… It’s what VXGI want to do but it’s not there yet!

Yeah that is pretty much what I’ve gathered from the many hours of research I’ve done on the topic. I just wanted to see how others dealt with the lack of dynamic GI on point lights. What alternative methods/solutions do others suggest?

Explore this thread. https://forums.unrealengine.com/showthread.php?70361-Inexpensive-Indoor-Global-Illumination-in-Alien-Isolation
Might give you some ideas!

I knew there was something about Alien Isolation, loved the graphics on that (and the heart-stopping gameplay). Superb blend of GI and dynamic lighting.

Can you “fake it” by adjusting the Post Process Volume “Global Illumination Indirect Lighting Intensity”?

I did a quick test and it seems possible. Especially if that room light is not moving, and the player can’t really look outside the room when in the room.

Which is my question. Is it possible to Lightmap using a Stationary Light to get the GI, then use the same light as a Movable Light. This way you get the GI but can adjust the intensity as you will, while adjusting the GI with Post Process Volume as above.

As long as that Movable Light doesn’t quite move then it seems possible… is it a good practise though?

Also, where’s the Lightmass setting to get GI but NO shadows. As in one gets “bounce lighting” without the shadowing. So that’s baked GI but dynamic shadows. I’m confused on this aspect. For example, let’s say you get baked GI from a Stationary Light that’s set to NO shadows. Does that mean you get the bounced lighting, then use that light as a moveable light for shadows while retaining the bounced lighting from the light (a kind of very “general” GI with a dynamic light)?

Edit: Maybe get baked “General GI” from a Skylight which casts no shadows but does bake AO, then chuck in dynamic lights to get your, well, dynamic moveable lighting?

Edit2: Playing with getting baked GI bounce lighting (Directional Light no shadows), then using a dynamic light (Directional Light with shadows) then using PPV adjust Indirect Lighting Intensity… Seems doable depending on the project. The PPV “workaround” could be very useful since you can change the Indirect Lighting Intensity as a player moves from one place (one volume) to another.

Edit3: To clarify, I’m no expert, just switching over from learning Unity to learning Unreal and coming from a PC gamer perspective.

EDIT: I’ve seen your project and concept art, stuff. I believe the methods below are possible due to the lights being fixed but just certain lights turning on/off. Again I’m no expert but I believe this and the next post is a much simpler implementation of the Alien Isolation techniques by combining dynamic lights with shadow-or-no-shadow GI lightmaps adjusted with Post Process Volume GI Indirect Intensity (PPV I’m sure easily manipulated with Blueprint or C++). To keep things simple as described below you may not even have to swap lightmaps in and out, just reuse the same GI lightmap.

Is this what you mean? Note: From “Lightroom” asset on Marketplace by Koola, GI baking at very low settings, very quick test, the screenshots below are for illustration purposes only (I put the wrong screenshots below, short of time, but re-tested etc and the screenshots below illustrate the concept nonetheless).

Light On (Possible: dynamic/moveable point light with bounce GI - lightmap of stationary light, keep the lightmap but make the light moveable)

Light Off (Possible: dynamic/moveable point light totally off, bounce GI intensity from lightmap of stationary light reduced (you can turn it down even more))

Light Green (Possible: dynamic/moveable light on green, bounce GI intensity from liightmap of stationary light tinted green)

Apologies for the third post, it’s super late at night and I want to make sure I get all the details down.

Asset from “Blueprints” by Epic Games on Learning.

Next: BOUNCE GI NO SHADOWS from SKYLIGHT, Directional Light Fully Dynamic/Moveable. *As per above post this should be possible with Skylight or other Stationary/Static Lights to get the Bounce GI and or Shadow GI then use with dynamic/moveable Directional, Point or Spot Lights.
Note: TURN OFF THE SKYLIGHT after you get the BOUNCE GI.

Proof Of Bounce GI: Notice the “bleeding” of brown floor colour onto the concrete on the left. Also notice nice baked AO, no SSAO, no SSR. (Someone please clarify regarding baked reflections using Lightmass?)

GI Lightmap Only Of Skylight (Get All The Bounce GI No Shadows, Adjust Intensity Later In Post Process Volume)

Dynamic Directional Light Only (“No GI Whatsoever”)

Combine GI of Skylight With Dynamic Directional Light (“Faked Dynamic GI”)

“Evening Scene”: Dynamic Directional Light Angle Changed, Intensity Changed, Dynamic Light Only (“No GI Whatsoever”)

“Evening Scene”: Use SAME Skylight GI Lightmap, Adjust Tint & Intensity In Post Process Volume, Use With Dynamic Light Only (“Faked Dynamic GI”)

COMPARE: “Evening Scene” STATIONARY Directional Light With Lightmass (“Real Static GI”) (Of course, below is very low Lightmass settings for illustration only)

Wow that is a lot, . Thanks for the replies. Your examples with the Skylight/Direction Light doesn’t really help me since most if not all of the GI will be coming from point and spot lights. The environment will be completely interior. There will probably be some light coming through some windows however. I’ve tried the PPV method before, but the problem with that is that it effects all GI. So it doesn’t work well if the player can see multiple lights at the same time and only 1 of them is being turned on/off.

The short answer is, nothing at the moment. Neither UE4, nor anyone really, has a good GI solution for quickly moving point/spotlights. The best I’ve seen is the hacky, and very environment specific reflective shadow maps used in The last of Us, or the, again very specific and environmentally constrained stuff used in Alien Isolation.

Regardless, unless you want to build the very complex and constrained solution yourself, UE4 doesn’t really have anything right now. One hack you could try is a small point light and a small “ambient” light attached to the same model. Doesn’t look great but it works, insofar as these things go.

Isn’t Enlighten in Unity 5 fully dynamic?

Here’s in action integrated with UE4

More info about it here:

From what I’ve heard that is super expensive though.

Enlighten has it’s own issues, it leaks like LPV, and does require baking.

I know, was only pointing out the fact it’s only UE4 that doesn’t have real-time gi (apart from LPV which won’t work indoors.)

Have you looked at AHR?

No worries, all the best with your ongoing search…! Let us know if you find anything suitable.

Enlighten requires static meshes baked to support the dynamic indirect lighting, however apart from that it’s “technically” dynamic. In other words, the lights themselves are dynamic, the meshes and geometry they affect are baked.

LPV does work indoors sort of if you mess with the settings. I’ve got LPV working on a small indoors section with no leaking, although one wall does glow for some reason, gotta look into that. Playing around with the LPV bias settings in a post-process volume and the actual wall mesh and material help greatly to reduce leaking.