Search Issue Tracker
Won't Fix
Votes
28
Found in
6000.0.8f1
7000.0.0a1
Issue ID
UUM-74735
Regression
Yes
Block compression leads to lightbaking artifacts in HDRP
Reproduction steps:
1. Open the “ReproProject“ project
2. Open the “Assets/Investments/01_Motivo_OnlyBathroom/Apartments/1-A-6-15“ scene
3. Open the Lighting window (Window > Rendering > Lighting)
4. Press the “Generate Lighting” button in the Lighting window
5. Observe the Scene View
Expected result: There are no Lightmap artifacts
Actual result: There are Lightmap artifacts on the joints between the floor and the wall
Reproducible with: 2023.1.0a21, 6000.0.8f1
Not reproducible with: 2021.3.40f1, 2022.3.35f1
Couldn’t test with: 2023.1.0a1, 2023.1.0a20
Reproducible on: Windows 11 Pro (22H2)
Not reproducible on: No other environment tested
-
Jesper-Mortensen
Jul 15, 2024 16:48
The root cause here is the BC6H block compression and HDR lightmaps. I am working on a fix to make the lightmap post-processing more resilient to this. But as a quick workaround I can suggest that you set Lightmap Compression to `None` in the Lighting Window.
Add comment
All about bugs
View bugs we have successfully reproduced, and vote for the bugs you want to see fixed most urgently.
Latest issues
- Crash on when D3D12RenderPass::SetupDeviceResources when opening FBX animation preview
- Serialization errors are thrown when "com.unity.render-pipelines.core" is added as a custom package and Graphics window is opened
- Character Joints unexpectedly rotate when a ragdoll is created using the Ragdoll Wizard
- Crash on GfxDeviceD3D11Base::DrawBuffersBatchMode when rendering the Scene view
- The shared EditorBuildSettings.asset file of symlinked projects is not updated when changing the order of the Scenes in Build Settings in one of the projects
Resolution Note:
The real root cause of the problem is that this scene uses BCH6 compression. This compresses 4x4 tiles and does not work well with tiles containing vastly different values. Due to texels under geometry that is marked up as "double sided GI" and some geometry marked up as "cutout transmissive" some texels come out completely black and not invalid.
Also, padding is 2 and packing is set up for a 2 texel gutter (the default). Because the lighting in this level is very intense the indirect lit values are ~10,000 and mixing this with black texels in BCH6 tiles causes compression artifacts.
The workaround is to set the padding to 4 in the Lighting Window. And "Min Object Scale" in "Lightmap UVs settings" on the Mesh importer to 0.5 for the room mesh. Then make the materials on the room fixtures such as panels etc. single sided for GI and remove the cutout transmission on them. This fixes the issue as pixels under geometry become invalid instead of black and lighting is interpolated into them.
Another workaround is to turn off compression for the lightmaps.