Hello all, I am trying to set up a sound effect system for an ocean shoreline, that changes your footstep sound effect based on how deep the water is getting. Now I know that you have to set up line traces and all that, but how do you get them to detect meshes that don’t have collision (the water), let alone detect how deep the water is? What is the primary setup in this case? Thanks in advance! 
You would use a system, that gives you approximation of your water surface on CPU.
You have to setup custom collision channels and stuff like that. I don’t know the details.
Maybe here you find some info Collision Filtering - Unreal Engine
What does a blueprint for this look like?