I can’t get ray traced reflections on a translucent material that is viewed through another translucent material. It falls back to rasterized reflections on the one behind. I’m using UE 5.5 and substrate materials. Is this even possible? If so, what do I need to do? I have max reflection and refraction bounces at 6.
As far as I know this is not possible with Lumen GI.
With Lightmapped GI + Lumen Reflections it should be possible, but in 5.5 this is broken and doesn’t work correctly because Lumen’s RT reflection/refraction won’t sample surface lightmaps.
you gotta use raytraced translucency.
that currently got some issues with volumetric fog in close range. refraction is not supported, yet (!?!). normal map is ofc supported, but removed for clarity. the plant is in nanite mode and fully supported aswell. area shadows are supported, but are ofc noisy. alpha masked shadows are supported for raytraced sun lamps. mega doesn’t have that alpha duplication yet. afaik it’s being worked on. the refraction bounces are the controller how many panes you can stack.
i tilted the panes, so… you should see 3 distinctive raytraced head and room reflections. and full passthru to the green block.
it is pretty feature complete of what you should expect a stackable dirty glass pane to look like. best looking glass without lumen noise in the reflection. : )
btw… @Arkiras it does reflect lightmaps in 5.5.3. which version you on?
this is plain baked gi. lights off, obvi…
Lumen reflections sample the volumetric lightmap, not surface lightmaps. Annoyingly, raytraced translucency will also only use volumetric lightmaps, including for refraction.
Really hard to tell what I’m looking at in this image.
I reported this back in August for 5.4 and it is still broken, no idea if there are any plans to fix it.
xcuse me. i know howto use the probe visualizers.
allow me a burst shot of my test level.
it’s not the volumetric lightmap. it’s baked gi lightmaps. : )
I mean that’s great and all but what is that supposed to prove?
There’s zero detail in your reflections, it’s impossible to tell anything from these screenshots.
5.5.3
Left: Raytraced Translucency
Right: Opaque Lumen Reflections
Both only reflect the VLM, translucency can only sample VLM through the surface.
Yes… it does. I’m sorry that you do not seem to understand what I am saying, but it is in fact relevant. Further, I only continued this because you asked me about it. OP has made their decision, I’ve explained and demonstrated as best I can, no point continuing.
I’m using dynamic lighting, with Lumen GI and Lumen reflections. When I change translucency to “ray tracing” I lose ALL reflections on the glass completely.
Image 1. Raster Translucency (with lumen refelctions)
Image 2. Raster reflections (showing no lumen reflections on occluded translucency)
Image 3. Ray Traced Translucency (zero reflections)
okay. hangover testcase build. and… it works for me. lumen gi and reflections. raytraced translucency. double sided glass. standard surface forward shading. i get a clean front/primary and secondary reflection bounce thru another layer.
shrugs
btw… @Arkiras i didn’t ask for anything. merely confirmed that it can use baked lightmaps or “gi maps” for reflections, if you want that. and i don’t like this test scene of yours. it’s a repetitive room. you’ve show that scene in the lumen thread before. it’s off-putting/confusing to try to visually trace/debug things. all good. yo : )