UE5 severe problems when rendering translucent and reflective materials simultaneously

Well, I gave the Transparency Sort priority as well as the Translucency Sort Distance Offset a go and neither of those made any difference.

An interesting thing I did find though is that, while nothing changes if I totally disable raytracing, if I go to a glass pane object’s Static Mesh and disable “Support Ray Tracing” all the objects show up again. Sadly, the panes don’t do their proper reflections anymore, but this might have to be my option if I can’t find a real solution.

@Durghan hmm it looks awfully similar to the issues in my initial post, despite not being the same distance-related problem, but I get the feeling that it’s the same rootcause… what kind of Global Illumination are you using? And what lighting system? What about Reflections and Translucency? I would play with Lumen vs. Ray-Tracing, then also Screen-Space Reflections vs. the other types. Last, but not least, I’d check the different Lighting Modes in my glass material and see how the different precision options behave (Volumetric Non-Directional, Directional etc., all of them).

Found this interesting “fallback” fix, as a patch-like attempt to solve this while UE is (hopefully) fixing their rendering pipeline so that it can render translucency correctly:


"I have a similar issue with translucent emissive objects: if they are masked and default lit, they emit light, but translucent ones do not. Additionally, they do not show up in reflections. Is there currently a solution for this? I’ve tried tweaking a bunch of parameters

I specifically need translucent materials for my VFX, which neither emit light nor appear in reflections.

Based on what I’ve read in the Lumen Feedback thread, the current best path to achieve this is supposedly to use the cloth shading model. Apparently it does not inject light into the ray-traced scene, while still being opaque.