We are doing this in our scene. I am controlling the “wetness” across all the meshes by using a material parameter collection. How I am driving this in my sequence is by making a simple blueprint with the event tick going into a “Set Scalar Parameter Value” that is referencing the material collection parameter, and I am changing the value with a float parameter that I revealed to cinematics(makes key-able for sequence). I had to make a blueprint so I had something to bring into my map that my level sequence could access.