Prevent Light from passing through?


What do i need to do so light does not pass through a mesh. i guess i need some sort of blocking volume but not sure how to do it.

Heres my problem… I have a furnace which playes a particle effect “Flame and light”, this light gets passed though my meshes and the light is shining where its not suppose to shine. “its not up your a**” this time :p"

Here is what my fernace looks like

And at this picture you can see the light passes though the mesh. you can see it faintly at the bottom edge and fading upwards

This is not a desired effect i want to have.

Any ideas how i go about constraining the light so it only shines out from the furnace hole ?