While true, missing AO is by design (or at least that’s my understanding of the issue after chatting with original author of GPULM). This is dumb. Even Quake 1 lighting baker had “AO”, because it just adds needed depth and “grimeness” to the scene.
1 Like
hi all.
Update April 2024
There is an official post that Windows 11 version 22H2 (winver) has been tested and working for Windows 11 and the new 5.4 BINARY Production release
Windows 11 version 22H2 and onward DX11 and SM5 works fine.
1 Like
Can someone else please confirm or disprove this statement above ^^^ ?
I was about to upgrade from Win10 to Win11…
1 Like
hi all Nice Dev …
any LInks For Unreal 5.4 GPU Lightmass but the Patch that is the File that we copy and past into Epic Directory …
thank you all
why not to just use 5.4 ?
@Miguel1900 Did you see my PM?
Hi @Luoshuang !
Sorry, the forum is behaving so weird lately. I have replied your PM right now. Thank you very much!
Hey @Jimbohalo10 
- I’m unsure where you gathered all of that information, however I wanted to clear some things up for everyone in the thread.
- GPU Lightmass is working with Windows 11 (DX12/SM6 [DXR Ultimate Drivers are enabled]) specifically with Release-5.4 - any issues specifically with Windows 11 we will do our best to investigate
- Windows 11 DirectX 12 DXR Ultimate Drivers are installed alongside Windows updates now - There is no standalone install anymore. If your windows version is above the recommended version for Unreal Engine 5 you should have it enabled by default. To check this, open dxdiag from the start menu, navigate to Input 1 and scroll down
- Windows 11 is definitely supported for Unreal Engine 5 - we have a mix of Windows 10 and Windows 11 machines daily testing Unreal Engine 5
I hope this clears up any confusion!
3 Likes
hi @Matthew.Ivey ,
Thank you /We have been unable to get any positive official comment on this.
I am sure everyone will be relieved that we have an official comment on this situation
Having some trouble with crashing lately.
In 5.3, I’m getting the following error:
Assertion failed: ResourceMap.Contains(Resource) [File:D:\build++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\RenderGraphValidation.cpp] [Line: 790] Resource at 000009B9D8AAB600 registered with pass LightmapGBufferTile is not part of the graph and is likely a dangling pointer or garbage value.
Has anyone else had this issue and have been able to resolve it?
@Matthew.Ivey
Hi,
I have been troubled by this issue since upgrading to UE5. The GPU Lightmass in UE5 works well on PC but performs very poorly on mobile devices. As shown in the image below, there are many small squares after baking. The reproduction steps are also very simple: first, perform GPU baking on the object, and then go to settings → Preview Platform → iPad Pro. In fact, this issue occurs as soon as you switch to the mobile platform.
Hi are you using the the new mobile previewer in
Using the Mobile Previewer in Unreal Engine
Have you loaded the new client end from Google play , Apple store.
There is a new version to support the new Thin Materials.
If you have the old version with the later version of UE5 the crashes occur
Android settings have to be set correctly in your project for Samsung.
Oh yeah there is a new version for Unreal Fortnite Creator 2.0 , use to crash in Creator 1.0 and so a new app with new drivers was created.
In summary the client software was crashing Fortnite Island Lighting so it got fixed
Like everything Fortnight does 
Android uses Vulkan drivers and CPU, like Fortnite. Very few mobiles have GPU on them usually software raytracing like Lumen.
1 Like
mobile devices always use low quality lightmaps, so you will always have disparity between what you see on PC and mobile.
1 Like
I agree that some differences are normal, but they shouldn’t be this obvious. Previously, in UE4.27 and when using LuoShuang GPU Lightmass, these small squares didn’t appear.
when using LuoShuang GPU Lightmass, these small squares didn’t appear.
That would be quite interesting. Can you provide a minimal repro scene for me to investigate? thanks
I’m very glad you noticed this issue. I used the UE-provided demo to reproduce it. This is a video effect that requires switching the view to Mobile Viewer. Looking forward to your response.
This is the test project in the video.
GPULightmassTest.zip
This week I followed the same steps but the build of UE failed with numerous errors. Suggestions anyone?
But do you have a demo scene where the squares DIDN’T appear? I think Luoshuang was asking for it.
This is ouor GPULightmass
And This is LMGPULightmass
Both of them DO disable the compress Lightmaps in world Settings.
This is enable compress Lightmaps for LMGPULightmass
This is a UE5.4 project can use LMGPULightmass
GPULightmassTest5_3.zip
So, this is a case where lightmap encoding doesn’t play well with texture compression.
UE has 2 encoding scheme, HQ (high quality) and LQ (low quality). Hight quality uses a variation of the popular RGBM (see Lightmap Compression in The Witness – Ignacio Castaño) encoding, RGBLogL, where R:G:B:LogL = 8:8:8:8 (BGRA8). For LQ, RGB with luminance quantized is used, which is 8:8:8. When no compression is used, the LQ encoding is actually not that ‘low quality’, see the comparison of HQ vs LQ uncompressed (please ignore the dark edges as I’m experimenting with something else):
However, when texture compression is used (BC1/3, dependent on whether there is an alpha channel, which HQ has. The RGB part is the same), we can tell the 4x4 compression tile pattern in both HQ an LQ:
LQ compression suffers more as it has less bits (I guess), yet the HQ one is not really much better. Now, the easy ‘solution’ for you is to disable lightmap compression which will result in 4x size. Or, if you can accept the quality of compressed HQ lightmaps and you are working with a programmer, try to hack HQ lightmaps on for the devices you are targeting. I don’t have experience of working with iOS so I could not help you on this part.