Im currently working on a building visualization. This building contains a lot of glass panels and I’ve noticed some problems with the reflections.
Glass is somehow reflected as opaque black instead of transparent. Is this a engine limitation or is the a fix for that. The only thing i found worked was to disable raytracing for the reflected meshes which makes them invisible in reflections but that is very unelegant since they also lose all reflections.
Secondly when looking from behind glass all glass panels seem to be invisible.
Would be cool if someone knew a fix for these problems.
I think the Glass reflections are still under work since the last time I checked reflections where very low quality across the board. Did you try Unreal 5.1 ?
Hi not yet but ill give it a try
yeah im aware that UE is not primarily a arch-vis program and feared that it might just be a limitation. thanks for the quick answer:)
(btw I’m using ray-tracing transparent reflections, without refractions if that makes a difference)
unfortunately from my experience, this has been an issue from the beginning introduction of raytracing in unreal 4.
A reflection of a translucent materials type only has its Albedo color+ Lighting picked up ( in this case, Glasses albedo being black) and is not raytraced,
no mater how many ray bounces you put on it.
works fine for opaque materials, just not transparent.
I’ve asked in many webinars, but perhaps my question doesnt come across? or there have rarely been archvis or automotive specialists on the talk.
this is particularly bad in Automotive lamps with detailed refractions and multiple lenses to look through ( all the unreal car example have had “choice” simple lamps that let them get by)
Id love Unreal to solve/answer this, or tell me " fool you missed this little tick box"
As the only option available at the moment in this case is to pathtrace, which leads you to question leaving your original offline GPU rendering application.
I found the best solution for now is to use this material setup for anything that’s being reflected black.
In my case I had context building’s glass reflecting dark so by using RayTracingQualitySwitch keeps the default look of the material but makes it look different in reflections. My setup in the screenshot makes reflected objects appear lighter by adding some Emissive Color and reducing Metallic so you can see more white Base Color.
Im using Lumen for general reflections. As far as I know there are only the options for raster and ray tracing reflections for transparent materials and raster reflections are more or less just color blobs.
I tried to use these settings but the material itself became white not just the reflections. Am I missing something with Lumen reflections, because I thought they dont work on transparent materials and you have to choose between raster and RT?
Im using Lumen GI+Lumen reflections in the project
The raster/raytracing translucency setting does not refer to reflections. Raster translucency will use Lumen reflections. Raytraced translucency gives you accurate refraction by raytracing the scene through the glass, there is a separate option to use raytraced reflections for translucency. The distinction isn’t really important though because neither of these features work with Lumen. You must use raster translucency, and lumen reflections.
Translucent lumen reflections are low quality in 5.0 which is why they look like “blobs”. If you need sharp reflections your only option is to upgrade to 5.1 and enable the “high quality reflections for translucent materials” option in the project or actor settings.
You are not going to fix this issue without using raster translucency, for the reason I already stated.
Your material should look like whatever inputs you wire into Normal of the RayTracingQualitySwitchReplace. You can see that my setup doesn’t have Opacity. That’s because I made a ‘fake’ non-transparent glass for my context which looked better but that won’t work in your case.
For your setup you can try having 2 Switches - one for Base Color going from black in Normal output to White/Light Grey in RayTraced input. And another for material’s Opacity input which uses a low value (0.1) in Normal input to make it look transparent normally. And higher value (0.5) in RayTraced to make it reflect more opaque milky white / any other colour in reflections.
This way your balustrade’s material should have a normal transparent glass look but when reflecting itself it will appear lighter in reflections.
