Hey all,
Is it possible to “properly” create a thin material that simulates something such as a lampshade - i.e. allows light to pass through, but isn’t transparent?
I see various workarounds that have been done, but haven’t actually been able to determine if the current build can simulate this.
i think there is not way,UE4 is based PRDF,but you want let light can pass through opaque material,that’s wrong,but you can simulate this.
for far objects - you can try masked with DitherTemporalAA node 
and - for what you need transparent but not transparent :)?
You can either make an emissive material, which works well for a lit lamp. Or you can use some sort of sub surface scattering.
Foliage materials work in a similar way.
You can use two meshes. One with a subsurface material and one with a translucent material.
Set the mesh with the subsurface material to not cast shadows and set the mesh with the translucent material to not render in the main pass.
See attached example of baked light using this technique.