Hello. I recently began to learn UE4, and at the present moment almost nothing I can do. I would like to do it myself, but unfortunately I have to admit defeat.
So, I want to make the backlight for windows. I tried to add a turned point/spot lights near the mesh, but this does not have the desired effect. I also tried to use emission, however this is too bright.
Please look at the first attached image. I would like to get something in between the left and right windows.
I do not know how to lower the emission rate. I would also like the wall around the window to be slightly highlighted. The second picture is just for example. This my experience on one old engine - there I got the desired result.
What you want to do is multiply your emissive map by how strong you want your backlight to be. The default value is 1, so if you find it too strong you can set it to a lower number. You can modify it further by multiplying a color over it to change the tint of your windows, take a look here 
https://docs.unrealengine.com/en-us/…erialNodes/1_5
To get a volumetric glow effect around the windows, there is a relatively easy way to fake it by placing fake glow volumes around your windows.
Edit: Im pretty sure the scene in your bottom example has baked in lighting. You need to check “Use emissive for static lighting” in your windows details panel and lightmnass will take your glowing windows into consideration when baking your lightmaps.
Thank you!