Luoshuang's GPULightmass

I have the same problem with 2080ti.

And I reinstalled everything. Drivers and UE4 too. It always crashes.

My only workaround to continue working now is to exclude my PC from building the light in swarm agent and using other PCs on the network.

Hi @MaximumDup
Thanks for the video helping to setup the VXGI 4.19.2 with the GPULightmass. I wonder if there is a way to use VXGI and GPULightmass at the same time in one sence.

Hi Guys, i Have same problem here… the first One is CPU Bake. The second One is GPU Bake. I dont Know why is So Black . what did i do is Migrate all Things ( CPU Project ) to GPU Projet. But is so dark. anybody know i solve it ?

Is anyone else experiencing black areas that affect only dynamic objects after building Volumetric Lightmap? Like this: Volumetric Lightmap problem: black box areas on movable actors - UE4 AnswerHub

I think I had this since before using GPULightmass, but I figured with so many people working with lighting, I might not be the only one experiencing this.

Happens to me all the time, but it’s just a bug of lightmaps not loading (invisible) after bake. You can still save as it’s just that the textures are not loading. It’s quickly solved by re-loading the level (I use streaming lighting levels), or making the persistent level hidden and visible again (which reloads the level).

I don’t think it’s the same bug you’re talking about. I see what you described all the time with HISMs. And that’s exactly what I do for it to go away. Reload the level.

My problem is that those black areas are affecting dynamic objects and they are always there. In my screenshot, the sphere, cubes and gate are movable. So they are the only ones affected by the Volumetric Lightmap. But there are samples there, enough brick memory and all. I’m trying to isolate the problem on a copy of the project without success so far.

Solved it! Bottom line, the problem was caused by RectLights with width/high set to zero. More details on Answerhub.

I always did it. With current GPU lightmass it does not work.
It work when I show the splotches BUG made by emissive static mesh. But now it seems not work at all.
Maybe there is some problem after Epic decided to use units for lights?
Luoshuang please help!

I’ve confirmed multiple times that emissive is working in the newest unified settings version. If it doesn’t try checking whether it is too bright that it is clamped by the FireflyClampingThreshold. If that is the case raise FireflyClampingThreshold to something like 10000.0

Hey Luoshuang. Thanks for the continous support and effort you put into GPU lightmass. It’s amazing! I wonder, do you have a roadmap for it? I ask because the official lightmass successor is still months away and it would be interesting to know how far you plan to take this. Cheers!

I’ve been silent for some time because I’m working on

  • New lightmap space sampling techniques, which aims at removing jagged shadows around edges / aliased shadows, and being more robust with UVs so that making lightmap UVs would be less demanding
  • Instancing support and lightmap mipmaps to reduce GPU memory consumption
  • Proper LOD/HLOD support. I may also implement per-LOD lightmap for (Hierarchical) Instanced Static Mesh Component so foliages can have proper lightmaps

Note that GPULightmass is still my spare time project. At Epic we’re working on DXR/realtime raytracing.

Wow! you are a f** master! love it!! :slight_smile:

Impressive work! This new GPULightmass will most likely become the standard for less powerful machines.

Also I think I speak for many when I say thank you **Luoshuang **for giving us something to work with until realtime raytracing arrives.

Keep us updated! :slight_smile:


Hi Luoshuang,
thank you for sharing your roadmap with us.

I have just couple more questions:

  1. Any plans of ETA for IES indirect lighting support?
  2. Same about Multi-GPU rendering, is it really so difficult to implement in GPULightmass?
  3. Any ETA for official UE4 support of GPU Lightmass?

Thank you.

is there any way to fix this?

Have you tried disabling texture compression in world settings?

​​​​​​ I am not sure if GPU Lightmass using multiple GPU [2 x 980 TI ] on same workstation. I am using swarm agent to distribute anothe workstation which has GTX 1070. Looks like each single card works perfect expect one of the 980 TI. Can someone explain if GPU Lighmass supports multiple graphic cards on the same machine? Thank You!!


it fixed bro Thank you so much

@Luoshuang Any chance you could make a build for the new 4.21.0p1 as well so we can test the goodies & fixes of 4.21 while not sacrificing your 100% essential gpuLighmass plugin? Just asking - no idea how much effort this would ask of you.

Hello, thanks a lot for your work.
So do you think your work will be implemented in the next versions of the engine? Like a full version “Ok” for production.

Realtime raytracing is obviously for now only marketing tech to sell graphic card and allow one or two pass with raytracing just for gadget… Days we will have a full raytrace solution running at 60fps are not before years. It’s taking too much performances for game on console and PC at 60fps, When I’m taking a look to the presentation slide for the Star wars cinematic (even not a full raytrace scene, with occlusion, reflections, shadows…), the timing for every passes is huge and it’s running the best hardware of the market. It will never run on next generation of consoles. So I’m wondering if Epic considers to push your GPU Lightmass at some point because it’s the real improvement since the beginning of the UE4 Dev about lighting (until the day we’ll have also real physical unit for main lights…).

Actually it’s costing a lot of investment to create renderfarm to use this oldish cpu system, even for big company like Sumo Digital. GPU lightmass is a game-changer for company doing realistic game running at 60fps, saving time, saving money. It’s so more usefull for now and nexts years than gadget raytrace (it will be future when we’ll have cheap hardware to run it).