First ,thank for the tip.I wasn’t aware of this option. Second, as a graphics programmer myself I wonder why UE4 can’t correctly render transparent object (usually the technique is to disable depth and render back to front order all the non-opaque).We are not talking here about intersecting geometry (which is indeed a problem) Maybe because of the deferred mode? I need to check if in forward rendering mode the same happens. If it does I still believe it is a bug unless something in the UE very long pipeline is preventing correct alpha compositing on purpose.