Epic's GPUlightmass

ph1rmacist · July 15, 2026, 12:59pm

A bug i found is that when Use Area Shadows for Stationary Light (In the directional light settings) is True while using a stationary directional light, separated meshes that use the same material get lines between them after moving some distance away from them:

Also increasing the r.screenpercentage makes the lines appear farther away

This does not happen when using CPU Lightmass, And it does not happen when Use Area Shadows for Stationary Light is off

I am using version 5.7.4

kotlet · July 18, 2026, 1:56pm

Thanks for the spotlight fix.

yujiang.wang · July 19, 2026, 8:25am

Looks like related to mip map selection. Could you send me a minimal repro project?

ph1rmacist · July 20, 2026, 3:06pm

Here, Created Using version 5.7.4

yujiang.wang · July 23, 2026, 7:37am

Release 5.8.0 2026.07.23

https://downloads.luoshuangfw.io/gpulm-releases/GPULM-5.8.0.exe
Back to release list

Fix issue with stationary local light shadow invalid texel detection

@ph1rmacist I don’t have the disk space to host multiple engine variations so unfortunately I can’t provide you a drop-in installer for 5.7.4. So you need to either:

If you want to use 5.7.4 you’ll need to build from source. Use https://github.com/AlanIWBFT/UnrealEngine/commit/2ec81b8838c6532720d94337272977fc5c6376d4 as base then cherry pick https://github.com/AlanIWBFT/UnrealEngine/commit/240a8cc6472c635c45edded8c5b7c1125242eeb4 on top and build to get a fixed 5.7.4 engine build.
Or upgrade to 5.8.0 and use the installer provided.

ph1rmacist · July 23, 2026, 2:49pm

Thank you so much for your work.