Lumen Emissive Material Reflects Black When the Shape is Too Small


Hi guys. I’m using lumen with UE 5.3 and and the ceiling lights have a luminescent emissive material. But they reflect opaque black.

So I did a test and made a cube and added the emissive material to the cube and it does reflect correctly on the glass but if you start making the cube smaller and smaller, a weird black shadow overwhelms the shape making it black. I tried the same thing with imported objects and objects created with the modeling tool and I still got the same result.

On the other hand, I was able to test this on a plane. When i got the plane to about 15% scaled down, the shape went black so I used the scale tool to scale it inwards (like flipping the normals, and then I was able to show the light at any size but that only worked for a plane and did not work for a cube for example.

In the attached images you can see the same cube with the same material. The only difference is the size. Notice how the small cubes lose the ability to reflect light after they become small.

This is driving me crazy since I need the reflection of those emissive to show. Does anyone have a solution to this. Thank you.

Hi there,

I know it’s been a long to reply But i encounter the same issue in my running Project, but Luckily i got the solution so basically you need to check your post process under the postprocess search the local exposure under that you will get the following Option


make Sure to put it as a default and check again whether its gone or not and let me.