Translucent Object Shadows and Ray Tracing

I’m having at least two huge problems trying to develop glass materials for a raytraced archiviz project in 4.24:

  1. translucent ray-traced objects cast opaque shadows (no light comes through the windows) - how can I make the shadow density match the object opacity?

  2. refraction in single-sided objects (planes) have wild IOR and aliasing (big jaggies - see glass pane at left) - is there a way to use single sided objects as glass or do we have to make everything double-sided geometry?



Hey dude, just change translucency box (post process volume) to RASTER, works well for me.

I’m having the same problem with translucent ray traced shadows in UE4.24… dark shadows with glass objects. I’m doing interior renderings but I’ve had to turn off shadows on windows so light will come through. Translucent shadows also doesn’t work with subsurface shaders anymore either. I was able to get it working with previous versions of UE4 for materials that would be used on curtains.

I’m not sure if it’s related but glass objects will even look almost black when ray traced shadows are on unless I turn off shadows under ray tracing translucency in the post process volume, the refraction looks correct but then the glass item looks like its glowing. Its really frustrating, I really need to get this to work… I’m not sure if its a bug or if there’s something I’m missing. I swore that translucent shadows were working in 4.23, but now is seems totally buggered.

Any help would greatly be appreciated. Thanks!

For me not working elementary translucency color shadows from stained glass.

Is “Transmission” enabled in the scene lights (directional, skylight, any others that are pertinent to the translucent objects)?

Hi, I’m sorry but about what I see in your picture shadow are properly traced. Have a look at the object opacity and I see the shadow respect the same opacity.
However you can even set translucency and property about it in material editor without effecting the entire engine set

Ray traced light transmission isnt supported, neither in 4.24 or 4.25, despite ray tracing apparently being “production ready” in .25

But it’s still a combination of rendering ray tracing and raster pipeline, as stated in the docs (sorry to quote those as it’s not always reliable). Thus, transmission would work if the correct settings are there, eh?