Triggering different events depending on camera perspective?

I’m still very new to game development in general but I have an idea for a project which features levels similar to how the game “Layers of Fear” (running on the Unity Engine) accomplishes scene morphing depending on perspective or whether you have an object in view of the camera. The effect I’m trying to achieve is when looking away, it’ll hide/unhide walls or add other objects that weren’t there before and you’ll see them when turning back around. I was wondering how that would be accomplished within Unreal Engine.
Thanks for any help!

Math… thats all you need. Remember outside of normal event you check condition and break the flow if condition is not met. So check camera orientation, make distance vector (subtract camera to object locations) and compare that vector rotation to camera rotation, you can do that in tick then player is in box.