Global Illumination/Indirect Lighting Not Affecting My Geometry


I created a mesh in blender of a small canyon with walls and a ground. I have brought the fbx into unreal, and added a directional light. When I build lighting, I am only seeing direct light. All shadows are pure black. I then added a sky light and built lighting again. Literally no change, still black. Since then, I have tried all settings, boosting intensity in the world settings, in the individual material, still no change.

Here’s the interesting thing… when I boost the indirect lighting intensity and build lighting, the CAMERA gets brighter and reacts to the indirect lighting. However my scene itself is still black.

Any help? Much appreciated!

I have also tried adding a lightmass importance volume, no change. With something like Maya, Blender, or even Unity, Global Illumination with even just one directional light would bounce around inside my canyon geometry. It should be visible, especially if I boost the intensity like crazy. And the camera icon IS reacting to it, just not the geometry itself. So I must be missing some step or check box somewhere!

Any help is greatly appreciated!

does lightmass give you any errors when building the lighting?

There are a few small rocks and shrubs in the canyon. Lightmass gives me an error on the shrub model for overlapping UVs. I’m assuming because all the UVS of the leaves overlap so they can use the same image. Would overlapping UVs on a small prop model cause lightmass to not light the entire scene at all? When I get home tonight I will certainly try deleting the model and building again with no errors.

Although the camera icon is still reacting to varying levels of GI in the scene, so it must be calculating it. I would think at least. It’s just the models that are staying dark.