Eevee has fresnel falloff that desaturates metallic material at grazing angle #51992

New Issue

Tobia · 2017-07-07T22:17:29+02:00

Tobia commented

2017-07-07 22:17:29 +02:00

I'm testing Eevee and I noticed a strange effect. I hope I'm reporting it in the right place.

System Information
Windows 10, Nvidia Quadro M500M

Blender Version
Broken: 2.80-3615350-win64-vc14

Short description of error
When rendering a pure metallic material with non-white base color, Eevee shows a fresnel falloff of the base color saturation at grazing angle.
Other pure metallic shaders, such as Cycles Glossy BSDF, show nothing of the sort.
Also looking at various real-world pictures of shiny colorful metals (copper, gold) show no discernible effect of this sort.

Compare the margin of this sphere in Eevee:

and Cycles:

Node setup is very simple, 100% metallic and 0% roughness:

In this case, with roughness at 0%, what Eevee is doing is akin to applying a clear coat to the metal (even though the Clear coat inputs are at 0%) because a clear coat would transmit and/or reflect light depending on a fresnel factor. This is confirmed by looking at real-world pictures of Christmas balls, which do indeed show this effect, being glass spheres that are silvered on the inside.

Exact steps for others to reproduce the error
Open this .blend file and add an environment texture with blue sky (for better contrast with the gold material):

eevee test 1b.zip

I'm testing Eevee and I noticed a strange effect. I hope I'm reporting it in the right place. **System Information** Windows 10, Nvidia Quadro M500M **Blender Version** Broken: 2.80-3615350-win64-vc14 **Short description of error** When rendering a pure metallic material with non-white base color, Eevee shows a fresnel falloff of the base color saturation at grazing angle. Other pure metallic shaders, such as Cycles Glossy BSDF, show nothing of the sort. Also looking at various real-world pictures of shiny colorful metals (copper, gold) show no discernible effect of this sort. Compare the margin of this sphere in Eevee: ![gold_eevee.jpg](https://archive.blender.org/developer/F654975/gold_eevee.jpg) and Cycles: ![gold_cycles.png](https://archive.blender.org/developer/F654976/gold_cycles.png) Node setup is very simple, 100% metallic and 0% roughness: ![nodes.png](https://archive.blender.org/developer/F654974/nodes.png) In this case, with roughness at 0%, what Eevee is doing is akin to applying a clear coat to the metal (even though the Clear coat inputs are at 0%) because a clear coat would transmit and/or reflect light depending on a fresnel factor. This is confirmed by looking at real-world pictures of Christmas balls, which do indeed show this effect, being glass spheres that are silvered on the inside. **Exact steps for others to reproduce the error** Open this .blend file and add an environment texture with blue sky (for better contrast with the gold material): [eevee test 1b.zip](https://archive.blender.org/developer/F655006/eevee_test_1b.zip)

Tobia commented

2017-07-07 22:17:29 +02:00

Changed status to: 'Open'

Tobia commented

2017-07-07 22:17:29 +02:00

Added subscriber: @tobia

Wolfgang Faehnle commented

2017-07-07 22:29:32 +02:00

Added subscriber: @mib2berlin

Wolfgang Faehnle commented

2017-07-07 22:29:32 +02:00

Hi, please add a simple .blend to reproduce.
It make the life of the developer much much easier.
I think the environment texture could be added from the dev to make your life easier.
(And the file smaller)

Thanks, mib

Hi, please add a simple .blend to reproduce. It make the life of the developer much much easier. I think the environment texture could be added from the dev to make your life easier. (And the file smaller) Thanks, mib

YAFU commented

2017-07-07 23:07:09 +02:00

Added subscriber: @YAFU

YAFU commented

2017-07-07 23:07:09 +02:00

Hi.
Some tests. The effect is also visible with pure metalic Principled BSDF connected to eevee material output. Glossy BSDF connected to eevee material output looks very similar to Cycles (Glossy and Principled on Cycles).

Hi. Some tests. The effect is also visible with pure metalic Principled BSDF connected to eevee material output. Glossy BSDF connected to eevee material output looks very similar to Cycles (Glossy and Principled on Cycles).

Sergey Sharybin commented

2017-07-08 15:29:08 +02:00

Added subscribers: @fclem, @Sergey

Clément Foucault was assigned by Sergey Sharybin

2017-07-08 15:29:08 +02:00

Sergey Sharybin commented

2017-07-08 15:29:08 +02:00

@fclem, mind having a look? Thanks!

Clément Foucault commented

2017-07-09 01:24:57 +02:00

Changed status from 'Open' to: 'Archived'

Clément Foucault closed this issue

2017-07-09 01:24:57 +02:00

Clément Foucault commented

2017-07-09 01:24:57 +02:00

The principled and Glossy GGX (no multiscatter) are nearly identical across the 2 render engines. Compare each BSDF node with itself and not a different one on each engine.

YAFU commented

2017-07-09 03:18:24 +02:00

Hi.
Here I modified the file a bit and packed a free HDRi to make sure we are all comparing the same scene:
eevee test 2.blend

Hi. Here I modified the file a bit and packed a free HDRi to make sure we are all comparing the same scene: [eevee test 2.blend](https://archive.blender.org/developer/F656082/eevee_test_2.blend)

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Eevee has fresnel falloff that desaturates metallic material at grazing angle #51992