Emissive light material doesn't work after lighting build.


I’m very new at unreal, I really like this this platform. So far I’ve solved all my problems with google, but I can’t get my head around this one.

I have a room with computers and I modelled some blinking LED-s on it (spheres with an emissive material that blinks on random moments). It worked very well until I added room lighting and then built the lighting. Now the room is lit well, but the LED-s have 0 light output. The lighting on the ceiling works (light bulbs with simple emissive material included).

Does it have something to do with that once you build the lighting, it can’t change in time?






I now noticed that this is not the only issue after build. When I launch the game, all my custom made materials don’t work (objects are using the default material instead). The materials I use from the StarterContent folder, all work well.

materials work fine when I right click launch the project. Still no blinking of LED-s though.

Problem solved, changed the LED spheres from static to moving. Now I have regular lighting + the blinking LED-s.

I did find the solution myself, hope this thread will at least be helpful for someone else.

If you are trying to get the material to emit light the engine can do this, but not very well. First of all I find that more often than not its too dark. If you make a material instance, there is a lightmass section and you can specify an emissive boost. Second of all if its BSP you need to select the surfaces and specify them to use emissive for lighting. There is a way to do this for static meshes as well, but I don’t recall where the setting is. It should be similar to BSP.

The catch:
It doesn’t emit dynamic lighting at all. Also the light generated is limited to (I believe) the initial setup of the material. In other words if you have a traffic light that starts on red. Only the red light will ever generate any lighting.

The good news is I’ve seen evidence to suggest that this may change in the future. However this is probably going to be in the more distance future.

As I said in my 2nd post and 2nd edit, the problem was solved by changing the spheres to Movable objects.