How do I set up textures in UE4 that have dynamic emissive light properties?

I want to do something similar, created a material where a scalar value parameter can be set to 0 or 1 to turn the emissive color on and off. My last problem is that I want it to be an event in the level logic, but I can’t figure out how to fetch and create a dynamic material from world brushes to set the parameter…