UE4 Tutorial: Light Propagation Volumes

How to set up and use light propagation volumes in Unreal Engine. Topics covered: Light propagation vlumes, editing the engine, static and dynamic lighting, post-processing.
Special thanks to Armando Alvarez and Mark Elliott for their notes on this topic.
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[@Lusiogenic]

Thanks a lot for this!

[@kenalpha3]

Im in UE4.27 and almost did this tut. But didnt when I saw that Build lighting would be disabled. He didnt say at what cost to performance or? But what worked for me is I added the Direction light and a volume, and 2 meshes. I selected the Light, then 2 meshes > then converted to Blueprint Actor > Harvest (replace). And this worked to make a light switch (after adding trigger code) for a Room. I forgot to select the Post Volume when making the BP. And I cant add that exact one as a Component in the BP. So idk if the Volume outside of the BP, but in the same area, is working to contain the Dir light to my room square only. (In the process of rebuilding Lighting after I added the Dir light.) But it works to get a box type area of lighting with reduced shadows, after I increased Indirect Lighting Intensity to 3. And angle to down. (I hate that we have to add front and back, and up lighting - to light something at all angles otherwise.) Edit: The Post Process Volume didnt work to contain the light to my square room. It's lighting the whole map even tho I didnt check the box he did to disable bounds. How can I add a Post Process Volume (limited area of light effect) to a BP, and pair with a Light that toggles on/off?

[@lovepepsi7477]

it was kind of crappy to get through all of this to find that LPV doesn't work with emissive materials, even after toggling on Dynamic Area Light in the material properties and scaling the supposed emissive material light injection in the post process volume.. not your fault of course, useful video regardless EDIT: nevermind, disabling DBuffer Decals in project settings and rebooting the engine fixes this! Works in UE4.22

[@jacobblueberry7085]

make tutorial on Distance Field mesh, AO, and GI

[@voicehead]

please*

[@rafasoaresms]

Didn't LPV get abandoned in a broken/unfinished state because Lionheart Studios (the people who were actually developing it) tanked? Last thing I heard (gossip and speculation) is that Epic was not gonna finish it because they're focused on RTX now. It's a shame, because I really prefer LPV over RTX for production since it's hardware agnostic. (although nVidia also has VXGI, which they say should work on AMD hardware once it's fully released)

[@MegaMitrandir]

but vxgi is separate from ue4 base and you need to compile your custom engine, and lpv is embedded in the standard version - I'm also voting for lpv, but ... we have what we have ...

[@IamNeighborlee]

Stupid, I mean for ONLY those who can afford rtx ? ya real fair ! NOT

[@MarcioSilva-vf5wk]

I think UE5 lighsystem(Lumen) going to use LPV at it finest

[@Polytricity]

Thanks for this but cannot seem to replicate it in UE4.21 which we are using for our project. Did they disable something somewhere?

[@jorgebarcellona8339]

Is it good for version 4.22 or does it have a problem?

[@sounddifferent3752]

No GI from spot and point light - its absolutely disappointing.

[@okaybutwhythough7456]

Nice 4.20 why am I like this...

[@Ingolmil]

LPV has been broken in 4.17 - no light from emissive materials. And it still broken in 4.21. RIP.

[@underscore00]

Yeah, I mean it's a technique that's still technically in development, so there are gonna be limitations.

[@Polytricity]

Ah, I'm not alone I see

[@lovepepsi7477]

try disabling DBuffer Decals in project settings, worked for me and i'm using 4.22

[@DexterHe24]

Anyone knows how to achive this on Point/Spot/Rect light ? Why the propagation volume only affect on Directional light?

[@ZeusLT]

why change lightmap resolution of the cubes if you make them movable anyway

[@underscore00]

Just a force of habit honestly, but I like to be sure :)

[@UnrealArtist]

Good thing to have in engine, but baking light method is a lot more cheap and better in quality :) Thanks for the tutorial btw :P

[@waltage]

so it's dead technology?

[@underscore00]

More like unfinished. It was originally developed by a third party game dev studio that didn't end up fully integrating the software - that's why it has to be enabled via config files.

[@2eea5y70]

Nice Job👍👍

[@theonlyartist1992]

Im on 4.21 and i can't get this to work. I do it all and i don't get the bounce light. I didn't get the weird lighting effect after you changed the project settings. Which makes me think something isn;t working.

[@peterbluesman]

yeah me too, went over it , didnt miss anything, just no effect at all.

[@theonlyartist1992]

@@peterbluesman glad im not the only one. Need to try on a later build. I don't understand why its so difficult to turn this stuff on.

[@darodism]

Yeah, but how would this run? Games still struggle with static lighting. Orrr is this solely for demos? Still waiting for games that look good with full dynamic lighting.

[@johnline]

thanks for the video. seems that i can't get Light Propagation Volume GI to work in 4.24 P2 Dx12

[@DviousDingle]

you still have that probelm?. i know this 1 one year old. If so it is built in the engine, no longer needed to edit console variables.ini

[@VirtualWorlds]

Hi mate! What happened to build lighting? It's disabled. Do we not use it anymore? Sorry if this is a n00b question. I'm still learning. =)

[@VirtualWorlds]

I guess we don't use it anymore! It says it only does precomputed lighting. Some of my meshes are still a little bright. I'm using Epic's Foliage. Any ideas what causing this mate?

[@VirtualWorlds]

It doesn't seem to have any effect apart from make my level look darker. The Light Propagation seetings under Post Process volume don't seem to work. Any help on this would be greatly welcomed! =)

[@VirtualWorlds]

Ok mate, I got it working thanks to this delightful tutorial of yours! =) The only thing wrong now are the static meshes. Meaning, they disappear while playing in editor! Do you know how to get the engine showing Static Meshes in game with Light Propagation Volume enabled. Would really appreciate any help on this! Cheers for the vid BTW it helps alot! =)

[@VirtualWorlds]

Ok solved it! My initial lifespan was incredibly low. I just set it to 0 and all is fine now. No more disappearing! SWEET!!! =)

[@underscore00]

Glad you got it working :) You're totally right about the built lighting - when using the light propagation volume, all lights are dynamic so there's no need to build lighting! Also good work fixing the static mesh issue :)

[@Vijay-hl4wf]

Ah, This is helpful, but will it be okay use in game environments with no day and night cycles, as you made directional light movable. and build lighting is dis abled too

[@waltage]

how about reflections and bounces?

[@gui205]

Very intresting, what's the impact on the performance ?

[@ethanwasme4307]

*r.LightPropagationVolume = 1*

[@desmadremexa4912]

Thats good :v

[@NekotTheBrave]

I did enjoy this one.

[@itszane6174]

Can you make a tutorial about crafting and inventory

[@GameTubegames]

can u upload widget text when character on the box trigger and remove when end overlap

[@milansamardzic9469]

Wow man, well done.

[@veltechok]

excelent

[@MoD-zf9lv]

thank you, really helpful video :)

[@mirakedits3286]

Can we make a class based battle royale or any class based game through ue4

[@prototy]

Yes. PUBG and Fortnite were both created on UE4, Realm Royale was created on UE3 and there are more in development so UE4 was actually the first engine to create a standalone BR mode.

[@jvjaviervargas2252]

Bro, u must not write that command there, there is an option in project settings to active it, then if u decides write it, find the file .txt called DefaultEngine and write it there. That has made my project crashing out.

[@utkankiziltug3520]

u should talk slower

[@Qubot]

RTX will kill this feature

[@ferlaur113]

It’s not a race! Take your time and articulate. Thanks. Nice tut apart from that!

[@ant1fact]

It was perfectly articulated. Anyone using a tool professionally will appreciate quick and to the point tutorials. Plus you can always slow down the video in the settings if you're having trouble following it.

[@EscapeCondition]

What tca said