But CPU Lightmass is so painfully slow… I guess it’s time for me to upgrade my aged i7-4790 and go the Threadripper route.
Yep, it is. However, it yields expected results.
@LuoshuangRequest; for people using streaming levels, would it be possible to add a dialog if you just want to calculate the current visible streaming level OR all streaming levels just like the previous lighting methods do? No biggie but would be nice.
Trying to wrap my head around this. I turn on raytracing to do the gpu baking, which obviously decrease my projects performance. Once all the light maps are baked am I able to turn off raytracing and keep the results of the baked GPU? or does raytracing have to stay enabled?
Any light you guys can shine on this is very much appreciated.
Another annoy8ng bug I have found using GPU Lightmass is that a hole made on a landscape casts shadows on whatever object you have under it. For instsnce, if you make a cave, no matter what settings you set, lightn wont come in the cave, it will be calculated just as if the landscape had no hole at all. Has anybody else experienced this issue too? I see no mentions of this bug anywhere on the internet.
Hey RedSeim,
Please report this as a bug using our Report a Bug form with as much information as possible so that the team can replicate the issue you are facing and hopefully find a fix! 
Hey guys. using 4.26 and if I port over a interior to a android device I get a noisy port. Using gpulightmass from epic seems to do this. Have you guys noticed this?
I also get the “lights need to be rebuild” message. Here is a screenshot if the noise i speak off. The scene on PC looks very clean like the CPU lightmass
ur going to want to use the console command to disable raytracing in your view port when doing this…
Is anyone else completely unable to use stationary lights with the new gpu baker? They bake just fine, but as soon as the bake completes, their direct component turns off completely.
Already submitted a bug report for this, but I wanted to see if anyone else had run into the issue because I have a 100% repro rate with a clean install and am quite surprised nobody else is reporting this.
is the official GPU lightmass already suitable for production or should I stick with former luoshang’s gpu lightmass?
I can’t get the same results. any tips?
If you are doing ArchViz, stick with old GPU Lightmass. If you are doing game dev, stick with CPU Lightmass. 4.26 GPU Lightmass is not production ready and won’t be until UE5.xx
It appears shadow casting needs to be enabled for meshes to generate bounce lighting? Any particular reason for this?
I noticed a couple issues with GPU Lightmass:
- All meshes are considered for two-sided shadows automatically. Putting a light inside of an opaque emissive sphere will cause the light to be completely shadowed. A level that exploits this encasing the world in a box will not see appropriate lighting with GPU Lightmass.
- No support for colored translucent shadows. Stained glass windows do not have any effect on GPU lightmass.
- Does not scale to large levels. I had significantly faster response with Production quality CPU lightmass over a very limited GPU lightmass for the same scene that didn’t have too many objects, but was set to a larger scale.
Because of these issues, I still can’t use GPU Lightmass for many levels and rooms in my project. I believe there are too many missing features to be considered production-ready. There needs to be a list of known issues/unsupported features.
Ok… got some new info on this. Looks like the denoiser is not being applied. If i do a live SLOW MODE gpu rendering and disable DENOISER… It looks like my screenshot. Dots everywhere. So my question would be… could the new denoised maps not being applied or not allowed to over write the CPU denoised maps? Does anyone know where the light maps get saved at? what directory? This problem is when you port to Android. I think the denoise isnt being applied.
gotcha. any particular reason why CPU is better than old GPU lightmass for game dev?
It just works? All features are there, unlike GPU Lightmass where there is always something missing.
HLODs dont work in old GPU lightmass correctly for example.
Hello Dear Fellas!
I Have been searching everywhere to try and find a solution to my problem, so far couldn’t fixed, I hope anyone in here can shed some light into the matter,
Basically I started learning UE4 (4.26.1) a week ago, and boy! it was a steep curve to learn but amazing at the same time, I’m an Architect and Visualizer, so I decided to start the UE4 Journey with a simple Interior Archviz, I am using UE4 Built-in GPU Lightmass, haven’t try the old one yet, but the issue seems that everything works fine, but when wizing around the space there are some black flickering lines appearing you can see in the video below.
https://www.youtube.com/watch?v=RGeFgcALfds
The lighting only took 6 minutes to bake and as you can see looks OK on the viewport and also in the packaged version but still though dont know what could be the problem.
I used the following parameters (also baked the light with 2048/2048) but the problem persisted
[I forced all the Raytraced effects to be OFF, and also tested with all the Raytraced effects ON but the problem is still present.
I have my GPU Drivers up to date in case you wonder, Tested Nvidia Studio Drivers and the Game Ready Drivers with the same results.](UE4 Bug? - YouTube)
I hope anybody can help me with this issue, Thank you very much in advance guys!
In case you wonder my specs:
Ryzen 3900x
64Gb Ram 3000Mhz
NVME 2.0 1TB
Nvidia RTX 3090
Best.
Julio