Directional light passing though materiel?


I am an absolute newbie at UE4.

How do you make a directional light pass though a material/object, like for example a roof?

What im trying to do it

Directional light shines on material that creates shadows with the use of a noise pattern, creating moving light shaft patterns.
I want these light patterns to hit a ground floor THROUGH a roof.

How do it make it so the directional light does not hit the roof material?



select object and uncheck cast shadow is the simplest.