Sounds like a plan!
Okie doke. I’ll post over on your AH post here a little after lunch time when I can get back to it and test some of the other parts you mentioned as well. 
[MENTION=4894]Tim Hobson[/MENTION]
Posted more stuff on AH
Also, the normal map issue and this UE 4.12 is the worst build for mobile VR - massive performance issues out of nowhere - VR and AR Development - Unreal Engine Forums might be somewhat related.
Moved the post out of bug reports since it’s content issue and not specifically a bug that lightmaps are broken.
I’ve left the post opened, but the conclusion here is that it was not a “bug” with lightmaps and them breaking, but all related to how content was setup and developed and not a bug with how the engine works. The post should either be marked as resolved by you or reworded to reflect the issue with your normal maps and materials.
Content issues that need to be addressed:
- Lightmap UVs are not using the 0,1 space effeciently.
- Lightmaps settings for the foliage need to use enable lightmap resolution and use the default resolution of 8 or lower.
- Material setup, specifically the normal map, for the landscape was the cause of the issue that needs to be addressed. Using a basic color or simple material resolved the issue with lightmaps looking broken.
I’ll post on your other forums thread here shortly because I was running some tests to see if I see the same performance drops you describe using your test project you provided with this post.
[QUOTE=Tim Hobson;581901]
Moved the post out of bug reports since it’s content issue and not specifically a bug that lightmaps are broken.
Well, I just don’t see how it is not a bug if single normal map yields artifacts, but as soon as it’s multiplied by flat normal map, artifacts are gone.
As I explained on AH, it’s not a content issue. It’s how it has to be set up for that particular use case when a single global normal map is used to cover all pieces of the terrain to provide large details for the terrain. This use case works for ancient game engines, so it should work for UE4 too :o
I am not sure what you mean by than, sorry 
If I multiply normal map by flat normal map (or flat color .5, .5, 1), all lightmap artifacts are gone (with or without foliage and while keeping diffuse part of the material as complex as it is now). I don’t quite understand what difference it makes, but it makes the difference
Thanks
Alright. It doesn’t make sense at all (or maybe I am overthinking it).
Even if I use simplified diffuse, I still get those pixelated artifacts when using normal map (normal map image plugged into normal map socket, nothing fancy):
full: https://s10.postimg.io/dw4ncpelj/ue4_broken_lightmaps5.png
It looks like compression artifacts, so I figured if I crank up resolution of the normal map image, artifacts should be reduced to minimum or gone. That doesn’t happen 
If I use tiling normal map instead of one giant normal map, I don’t get those artifacts (but also don’t get nicely defined terrain).
Is there a way to have RGB normal map instead of DXT5 normal map asset ?
I’m having the same problem.
I am using some modular walls that worked just fine. After re-installing UE4, some of the walls suddenly were significantly differently lit. Nothing seemed to help, only migrating everything to a new project (so glad that helped because building
lighting takes so much time, especially when you think you’re done with something and then such an issue occurs).
I don’t really understand though why the problem occured so suddenly. What also fixed it was using stationary lighting, but I don’t want to use that, also it was working perfectly fine before. I did not change the materials, models or anything.
Now the project I migrated looks exactly the same as the other one with the same settings, but in one project the lightmaps are broken and in one they are fine.
It’s year 2022 and UE4 is still screwed when it comes to lightmaps/shaders/who-knows-what:
Most fragile engine ever 
That doesn’t look like a lightmapping issue, the effect looks like z-fighting for the whole scene but I don’t know why it would do that.
Now that I am looking back at it, yes, it does look like z-fighting, but crazy thing is that if I switch to Android Vulkan preview - it looks perfectly fine. Switching back to SM5 - I get this nastyness