Greetings, I’ve been looking around on the internet for about 1 hour to find a solution for my problem.
When I try to build lighting it gets stuck at 90% all the time and doesn’t continue. I’ve waited for 30 minutes at one point to see if there was just me being impatient. But building light maps for a Light Quality of “Preview light” for a scene with 8 static meshes which are properly unwrapped with both a light map and texture map shouldn’t take that long.
I tried removing 2 meshes from the scene and it’s now stuck at “Building Lighting 88%”. I removed 4 more and it is now stuck at 83%. I just left one single model in the scene, and it’s stuck at 80%.
It’s a brand new project for 4.9.1, Blueprint First Person, new map with no starter content.
There is a Skylight, the standard sky-sphere, one Directional Light and one atmospheric fog in the scene.
I’ve tried to remove the Cache from SwarmAgent and revalidating it. I have also been in the Appdata / Local folder and removed everything from the UnrealEngine folder (Sort of making a factory-reset of the program).
I also opened up the project called Realistic Rendering (The apartment with the red leather couch and good looking enviroment and did a preview rendering. Which took around 15 seconds, and completed.
I found a solution, but it is far from logical! The lighting is not able to build when I remove the content from the First Person project. So if I remove the folders the lighting wont build. But still, why?
I fixed it, sort of… But I don’t know how… Which makes this whole mess even more “not so logical”. I reinstalled Unreal Engine 4. So I essentially removed it from my system along with all the other files… Then reinstalled it… Made an empty scene, named it test and imported my models. It didn’t work and the Build lighting got stuck on 90%. So I removed it and made an empty scene again. Slowly wrote down everything I did so that I knew when I broke the build light button. Did everything I did before and It worked… I successfully built all the lighting without any trouble. Weird… So if anyone have some explanation for this weird thing that is going on, please share.
And now I broke it again and figured out the issue… I can’t build light without a floor piece, My models are all walls… But without the floor piece the build process wont complete… At least that is what I think it is.
This is a known issue right now that is reported with UE-20782. It’s still being investigated at the moment.
There appears to be a few things that can cause this to happen with the light builds where it appears like it is stuck. Keeping the template floor in the level seems to work, along with a basic BSP box at it’s default size, and a few other methods. We’re trying to get this solved quickly, and if we end up doing a 4.9.2 Hot Fix, which is not guaranteed, we would like to see this get fixed and pushed out with that.
I’ve added this post to the original ticket and will update once this has been resolved.