Experienced the same problem with splotchy lightmaps. The lights were placed very tight to the ceiling / fixtures (maybe 1cm). After moving the lights down 10cm the splotches were gone. Maybe the indirect bounce just needs a bit bigger gap?
I have a problem. The progress is stuck at 99%.
and. the first few times were normal, and suddenly this problem occurred.
I was having this RAM problem, how much I used lightmaps of 1024, 2048, 4096. If that is the case, try reducing the sizes and testing.
Did anyone solved the black dots, that appeared (in my case) on the highest quality? I dont have any emissive materials in the scene, but I might overlooked something. I am not sure, why these artefacts ocured, maybe too old hardware? (nvidia 650m) But I am thanks to this finaly able to bake bigger scenes than before, its just sad, that I am stuck to using middle quality preset.
I don’t know If I am not installing it correctly or my gpu is too weak for this to even work. But I work on a laptop with a 840m and I copied the contents from Binaries and Config to C:/Epic/Engine- respective folders.
Thanks for this gpu lightmass baker. Was definitely very fast :- )
Good evening, I ask for your consultation on this image. On the left side, you can see the light mass CPU and on the right the same scene with the light mass GPU.
UE 4.19.2
Is there a way to get the same result?
The performance of the GPU lightmass is excellent but the quality of indirect light is different.
I used the GPULightmassIntegration-4.19.2-UltraHigh preset
Do you have something to give me?
Did I wrong in setting some parameters?
Thank you all.
Saul
Any idea if GPULightmass will be available for 4.20 release ? (I don’t mean officially built into 4.20, but a version of plugin built for 4.20) ?
Is this still in development?
@RTView I noticed this as well. CPU lighting seems better with soft lighting as u can tweak the lightmass parameters. GPU lightmass is very limited in this area and no parameters can be tweaked. I had this problem but the fast baking was a better option rather than waiting for too long. Maybe increase the lightmap resolution?
I also experimented with koola’s ue4 interior daylight scene, the CPU captured the soft lighting better as well. I am not sure if gpu lightmass recognises light portals too. I gather Luoshaung is currently working with EPIC on a new lighting solution together with some other high profile renderer people. Hopefully we hear about it soon.
To me the CPU version is over blurred while the GPU is subject to noise. By using Irradiance Caching the CPU solver effectively blurrs indirect lighting and skylight direct lighting. What is actually concerning in the GPU version is that it lost the bounce from the direct lighting.
A good way to get a ‘ground truth’ reference is to set the indirect lighting level scale to something like 0.01 and run the CPU solver. I’m still hesitating whether to add such a ‘smoothing solver’ (which means more bias) to the final version.
Exactly, I see that you fully understand my problem. The blur of the lights is not a problem for this moment
The rebounds of direct light are not there in this scene.
Or rather they decline very quickly.
If I set the parameter - World Setting - Num Indirect Light Bounces to 1 or 100 I get the same result.
I’m doing something wrong?
@** **Will there be a 4.20 version of your wonderful plugin? Although there are many many nice new features in the new 4.20 release, without GPUlightmass it still feels like a step back to me. Crossing fingers…
For 4.20, unfortunately no…
We are targeting future releases to give you a fully functional, vender agnostic and bug-free (especially darken corners, jagged edges and incorrect bounces, etc.) version to use.
Do you think we’ll get it by 4.21 or is it more likely to be in 4.25’ish ?
Woohooow a sign of life. Sounds epic 
Will you share more infos as development progresses?
** still waiting for your 4.20 gpu version your really big help now testing baking my project version 4.20 1 hour
4.19 with your magic baker 10 min only., Now decided to stick on 4.19**
We got multiple computers here, so popped the project on another one with 32GB of memory. It eats up roughly 29GB, starts BVH then Lightmass crashes. It’s a huge letdown, because on smaller scenes it works so amazing and so fast. I guess nothing is keeping us on 4.19 anymore, as long as this is happening here.
me too 
Did you ever figure this issue out?