Solution to blurry reflections on translucency

Development Rendering
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1

Hi,

I am working on a car configurator in UE5 and I got stuck with the issue of reflections on translucent surfaces being very blurry, which is quite obvious on car windows lit by HDRI panoramas.

I have figured a workaround solution. It appears that the SingleLayerWater shading model will allow you to get full resolution reflections and there is a way to make it behave almost same as the Thin Translucent glass model:

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The left is Thin Translucent Material with this setup:
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On the right is SingleLayerWater material with this setup:
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Set all inputs of the SingleLayerWaterMaterial output node to 0 except the ColorScaleBehindWater, which you will use the same way you use TransmittanceColor in the Thin Translucent shading model.

Then set opacity and roughness to 0.

There there’s a bit of shenanigans with the specular input to compensate for excessive reflection fringing the material can cause under certain scenarios. Just set it up the way I did (make sure the B value of lerp node is at 0.5) and use the FringingCompensation parameter to treat the fringing if you wish so.

That’s it. This should give you a workaround for blurry translucent reflection at least till 5.1 is out :slight_smile:

2 Likes
2

hi, just wanted to thank you, since I was trying to find a solution since forever, and yours it’s the only one that actually works and it’s the single best improvement I’ve seen from an user since the release of UE5

3

Thank you for this solution. I do have one issue tho. The glass is reflecting the skylight and not the environment around it. Do you know a fix to that?
I attached an image- the top left is carpaint and the bottom right is this material. It’s inside a building but I just see clouds.
2022-07-27 01_31_29-Window

4

You’ll most likely need to use an HDRI capture of your scene for the skylight. Afaik the reason this solution ‘works’ is because Single Layer Water doesn’t support Lumen reflections so it will simply reflect the skylight capture and specular hotspots of lightsources in the scene.