Making box mask line up with another box/actor

Hello! I am trying to achieve an effect when one cube cuts through another, think like an overlay when the player’s sword is passing through an object. I wanted to rotate the blade and then also rotate the mask but I can’t figure out how to rotate the box mask. I have tried this but I am not sure this is the right approach:

Here is a drawing of what I want:

If anyone has any ideas about how to do this that would be great! Also let me know if this is just the wrong approach haha - I just moved over to unreal from unity a week ago so still getting used to it :slight_smile: