Warping under glass

Development Rendering
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glass
glass1920×1150 179 KB

I’m working on a glass material for a watch but for some reason the watch face underneath the glass gets warped when viewing from different angles

The watch face itself is just a flat texture. It looks warped under the glass depending on how you move the camera which looks really weird. I’ve tried making the glass 2 sided but that just made the watch face texture darker and nothing else

I have a feeling it has to do with the refraction or the normals but I’m not sure what I’m doing wrong. I followed a tutorial to make the glass material. This was imported from Blender and it worked correctly there

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The ridge of the glass is rather high, probably causing the deform. Most watches will have the edge practically even with the rim of the watch.

You might try the new material model called “Substrate” (exerimental). It has a more accurate layered approach to materials.

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That’s actually how the glass is supposed to be on this type of watch

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Have you tried adjusting the Fresnel parameters? Try hooking up the Fresnel node to the color node to see where the falloff is taking place. Perhaps that’s the part that is different from blender.

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Refraction in Unreal engine behaves very interestingly on account of it being real-time.
Raster refraction in Unreal engine works via screen-space warping (last I knew). It’s limited in what it can refract to data based on screen, and basically has all the same limitations as SSR. I’d first render out your scene with the path-tracer just to see what the ground truth will give-you, and that can help you diagnose if it’s a lighting limitation or a material issue.

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After some more testing I’m pretty sure it has to do with the IOR. If I lower it to 0.9 or lower than it fixes the warping issue but then it does not look so much like glass anymore, just looks like a transparent layer