Lods should work fine. In 4.24 though, if you have UE create LODs the lightmap channel is set wrong and so artifacts are all over the place.
Putting the proper lightmap channel manually can crash UE. Its been reported and fixed and will be in 4.24.2
They don’t and said LODs are going to give me headaches, which is exactly what happened (as you can see on the pic). LODs are handmade, not generated by UE4.
I rebuilt lighting with CPU Lightmass and not only got no artifacts at all using Preview settings, but also got nicer lighting in general (especially ambient lighting).
I am thinking GPU Lightmass was made with in mind (it seems like I only got good results, fast, using it for indoor lighting and always had issues with outdoor lighting and LODs).
@ Strange. I never had any problems until the 4.24 lod-bug but I’m not doing any landscapes - just .
We can only hope the new solution Epic (and ) are working on will fix landscapes too. Still no word/sign when it will be in beta though.
Well, if you do , why do you even need LODs 
That terrain is not Landscape. It’s a bunch of static meshes made to match seamlessly regardless of LOD.
@ I need the LODs because the objective is to view the viz on Quest.
Not to drag this any further but I still fail to see why LODs would go wrong;
GPUlightmass is just another way to calculate the lightmaps. Unreal only calculates them for LOD0 as far as I know (tested this a while ago).
If manually created LODs have their lightmap UVs in exactly the same layout/position as LOD0, they would just re-use the same lightmap solution.
If artifacts are visible, I expect the uvs of the manually created LODs are not perfectly matching the internal layout of the LOD0 uvs.
Due to the LOD bug currently in 4.24 you can’t test it now but when 4.24.2 is here, you could test the LOD + GPUlightmass by just importing one of the meshes and have UE auto-create a few LODs. Run GPUlightmass and no artifacts should be visible.
i try in 4.23 , it is correct lod!
@tc22 You’re right, in 4.23 LODs and lightmap channels work fine. For now you could; import your mesh to 4.23 -> generate lods in 4.23 -> migrate to 4.24.
Lets hope they will release 4.24.2 soon.
UE4.24.1 GPU LM vs CPU LM
levels r identical and all parameters same. just skylight and 1 rectlight.
Compare : CPU vs GPU lightmass - Imgsli
With GPU lm there r no bounced from rect/spot/point light.
Question, do you guys know if its possible to bake “raytrace” shadows using gpu at all? I have a directional light test and set to stationary, but after trying lighting bake the shadow softness goes sharper and not soft as intented with a high softness value and raytrace shadows. Thanks.
Has anyone struggled with combo of GPU lightmass + Virtual Texturing for lightmaps? I’ve tried it in small interior+a bit of exterior and was getting warnings that VT couldn’t allocate from pool, while lightning was incorrect - full of artifacts/blacks. I’m guessing it’s a memory issue, but I’m still a bit skeptic about it - none of textures were converted to VT, so only VT lightmap is faulty there/using any resources, plus scene is really small in terms of meshes, GPU has 8GB VRAM and there’s 32GB RAM too. Could be that GPU baker and VT lightmap are somehow crashing in VRAM territory?
Can I use it in 4.24.1?
It is working! Thank you!
Is it recommended to update? Using the previous version (4.24) in 4.24.2 and it seems fine.
Currently running a project using VTs for lightmaps and GPU lightmass, everything appears to work fine. What engine version are you using?
I’d advise against overwriting a newer version of the engine/editor with older versions of GPU Lightmass. If you look at the binary bundle, you’ll see that one of the modified files is UE4Editor-UnrealEd.dll. By overwriting this file, aside from risking potential instability, you’re also missing out on whatever fixes and improvements the new engine version / hotfix brings, that are part of this particular module.
**This is from another planet!! **
I run it with 4.19 on my private VR project. Before I was fighting with light bleeds, splotchy shadows, lightmap seams … bake times >3 hours…
NOW… ~8-10 minutes bake time!
And no more light bleeds, no more splotchy shadows everything (mostly) is fine!!
This should be a build-in!! Hope Epic will buy it!
Thanks sooo much for this!! Unbelievable!!
Hi guys! here show a scene with gpulightmass + HDRBackdrop, thanks !!.
GPULightmass is awesome! 
Its just sad, that the skylight cant be stationary… is there any possible workaround? Maybe a second skylight set to movable for the dynamic foliage? Any Ideas?
I’ve checked just now, and it just isn’t there, so is it a certainty I don’t need cuda SDK for this to show up ? Latest nvidia driver for GTX 950 2gb.
Thx
I didn’t install cuda sdk, I only have the latest driver installed (I have a gtx 1070 8gb).
I don’t know, maybe it doesn’t work on gtx 9xx cards 