Local Post Process


I’m trying to create post process material that will allow to enable post process effect on specific area far from player.
Main goal is to “highlite” certain area, ideal long term goal will be to figure out how to create something like path from it.

I manage to find tutorial about creating local post process, but i can’t manage to get it work properly =/.

My material:

Post process on( with only saturation set to 0 )

Post process off

Material Blandable location is set to “After Tonemapping” if i set it to “Before Tonemapping”. Post process acts as if there in no mask in materiam.

Any idea what did i miss?