- Control the auto exposure of your lighting scene by searching it in project settings.
- Rebuild the lighting.
- Create a folder for your emissive materials in your unreal engine content folder.
- Create a new material.
- Add some geometry to apply to your material in the viewport.
- Open your emissive material in the material editor.
- Make a constant 3 vector and add that to the emissive colour pin in your material.
- Add the material to your material and duplicate the object with Alt+move (click and drag)
- Create a material instance of your first emissive material.
- Rename the new instanced material.
- In the original/master material right click on the constant 3 vector and convert it to a parameter.
- Name the parameter.
- Go in to the 2nd material instance and use the parameter to change the colour of the 2nd material.
