Vr look at trigger

Hi , I have a loft i have created for VR in Unreal. I want to change materials of the walls and floor.

My floor is one static mesh with one material, my wall is one static mesh with a few Material ID’s.

I want to change materials of these interactively,

there are tutorials for this , however what i want to do is, I want the user interface to change the materials to pop up when i look at the wall or floor and press a button on the controller .

anyone have a idea how to do this ?