Why aren't my windows showing any reflections?

Development Rendering
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1

I’ve been trying to fix this issue for a while now with no luck. Seems like a very basic request from an Archviz perspective, but surely there’s a way to show reflections on a glass window? Does anyone know what I’m missing here? Any help would be hugely appreciated!

LS_DiningView_559_0000
LS_DiningView_559_00001920×1080 204 KB

LS_HallwayView_468_0000
LS_HallwayView_468_00001920×1080 214 KB

LS_RearView_336_0000
LS_RearView_336_00001920×1080 403 KB

I’ve tried the following to fix this:

  • “support hardware ray tracing” is turned on in project settings.
  • “use hardware ray tracing when available” is turned on in project settings.
  • DirectX12 is checked in project settings.

in my post process volume:

  • Global Illumination is set to Lumen.
  • Reflections are set to Lumen.
  • Lumen reflection ray lighting mode is set to “hit lighting for reflections”.
  • Ray Tracing Reflections is set to “include transparent objects”.
  • Rendering Features > Transparency is set to “ray tracing”
  • “infinite bound” is checked.

My glass material has the following properties:

  • base colour 0
  • specular 1
  • roughness 0.05
  • opacity 0.1
  • IOR 1
  • blend mode “translucent”.
  • translucency > screen space reflections is unchecked.
  • translucency > lighting mode is set to “surface forward shading”.

I’ve tried using planar reflections which are a) super laggy, even just for one window and b) don’t actually seem to show any reflections either! I’ve also tried using Relfections > Method “Standalone Ray Tracing” which just seems to make everything very blue… - please see below for that.

LS_RearView_336_0000
LS_RearView_336_00001920×1080 393 KB

LS_DiningView_559_0000
LS_DiningView_559_00001920×1080 209 KB

LS_HallwayView_468_0000
LS_HallwayView_468_00001920×1080 210 KB

I hope that’s enough information to help find a solution.

Thanks :slight_smile:

2

Depending on your version you may have a “High Quality Translucency Reflections” setting in your postprocess volume. Try that first. Also go into the visualizer mode and select lumen reflections to make sure surfaces look good there.
Unrelated, you generally don’t want to set specular to 1 in unreal. It uses a range of 0-8% specular for 0-1 and real glass should supposedly be 0.5 (which is the default) aka 4%. You can ultimately set it to what you think looks good of course, but it won’t be physically accurate.

3

Go to post process → translucency → set raytracing type from raster to ray traced, check the box before the word “refraction”, and uncheck the box after the word “refraction”.

play with the glass material opacity in your node setup until you have something nice.

cheers

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