Light source, Visibility + collision Question

Does anyone know how to make it where wherever a cone of light shines (cone attenuation) onto an invisible-by-default material it becomes visible? and wherever it is visible(mask/alpha?) then collision = true?

The way I was thinking was if light =1 visibility = true. If visibility (alpha/mask?)= true add collision.

But how would I do this in blueprint? Is it even possible to do with a light source? or something else that matches the edge of where the light shines? Thank you.

Another way of thinking of what I mean is wherever the light shines it paints a mask.
The light could have a hidden collision object/volume that is attached to actor that other functions are based on.

Hi Yourname942,

We have a tutorial on location based opacity here: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums. I’m sure you could modify the end result to make the only area shown is that which has lighting.