Light Building stuck on 96%

Hello there. I am having an issue with building the lighting of my scene.

Everything in this scene is a static mesh besides the doorframe. Yes that’s right, the floor including the lower middle and the ceiling with the upper middle are both static meshes. The surrounding walls are one static mesh too. Same with the doors. Every time I build the lighting it gets stuck on 96%. One time I left it in the morning to build and came back from school to find the editor frozen. In the lower middle of the floor there is also this problem with the reflection. There is a triangular shaped area on the floor that displays reflections incorrectly.

The screenshot of the problem is here


Can someone help me out please?
Thanks! :smiley:

Which version of UE4 are you using? If its 4.9, there is a strange bug with the lightmass importance volume, try to rescale the volume to 10.10.10 and it should continue to render. :slight_smile:

I am using 4.9 since I for some reason can’t upgrade my project to 4.10. It won’t compile the project dll. And when I go to the source and compile, the visual studio projects don’t not load.

Its a known issue of 4.9, & they supposedly fixed it in 4.10. I am still using 4.8, & it works fine. I may check it when I upgrade to 4.10, but the release note, the improvement is not significant for the game I am making, so I have no urgency to upgrade to 4.10.

If have more than 4 spot lights colliding, they might be the problem. Try to reduce the radius so they don’t collide with each other.

So I got my project working on 4.10. The light building problem is fixed but the whole room turns out like this in the screenshot:

I changed the Lightmap Coordinate Index to 1 in each of the static meshes so Lightmass uses the right UV map on each static mesh. But this has caused the lighting to become like this.