Eeevee SSS Artifacts with Subsurface Translucency on #72695

New Issue

David Mikucki · 2019-12-25T21:03:57+01:00

David Mikucki commented

2019-12-25 21:03:57 +01:00

System Information
Operating system: MacOS 10.15.2
Graphics card: AMD Radeon Pro 5500M 8 GB
But it's worth noting I've also seen this on Windows machines with Nvidia cards.

Blender Version
Broken:2.81a (release), also broken in 2.82 latest alpha (December 25)
2.80 seems to have a similar problem, but it looks a little different and maybe not as extreme (though I haven't tested in all lighting situations)

Short description of error
When working with high contrast lighting setups, materials with SSS and subsurface translucency turned on generate artifacts that look a little like banding. This can be reduced to some degree by raising the shadow cube size, but I've yet to see it disappear entirely. This is especially frustrating since these are the exact kinds of lighting conditions that can make SSS really shine.

Exact steps for others to reproduce the error
You can get this by setting up a material with SSS, scaling down the SSS scale, turning on subsurface translucency, turning off or lowering the environment lighting, then lighting the object with the material from the size. It can be finicky to get it to occur sometimes depending on your model and settings, but I've encountered it in a number of ordinary situations

Probably the easiest way to reproduce it is to just load up the attached blender file and hit render or turn on the viewport

mnkysss.blend

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).

**System Information** Operating system: MacOS 10.15.2 Graphics card: AMD Radeon Pro 5500M 8 GB But it's worth noting I've also seen this on Windows machines with Nvidia cards. **Blender Version** Broken:2.81a (release), also broken in 2.82 latest alpha (December 25) 2.80 seems to have a similar problem, but it looks a little different and maybe not as extreme (though I haven't tested in all lighting situations) **Short description of error** When working with high contrast lighting setups, materials with SSS and subsurface translucency turned on generate artifacts that look a little like banding. This can be reduced to some degree by raising the shadow cube size, but I've yet to see it disappear entirely. This is especially frustrating since these are the exact kinds of lighting conditions that can make SSS really shine. **Exact steps for others to reproduce the error** You can get this by setting up a material with SSS, scaling down the SSS scale, turning on subsurface translucency, turning off or lowering the environment lighting, then lighting the object with the material from the size. It can be finicky to get it to occur sometimes depending on your model and settings, but I've encountered it in a number of ordinary situations Probably the easiest way to reproduce it is to just load up the attached blender file and hit render or turn on the viewport ![monkeysss.png](https://archive.blender.org/developer/F8244314/monkeysss.png) [mnkysss.blend](https://archive.blender.org/developer/F8244315/mnkysss.blend) **Exact steps for others to reproduce the error** Based on the default startup or an attached .blend file (as simple as possible).

David Mikucki commented

2019-12-25 21:03:57 +01:00

Added subscriber: @davidmikucki

David Mikucki commented

2019-12-25 21:07:57 +01:00

Here’s a render showing the problem.

Here’s a render showing the problem.![monkeysss.png](https://archive.blender.org/developer/F8244319/monkeysss.png)

Daniel Bystedt commented

2019-12-26 00:08:51 +01:00

Added subscriber: @DanielBystedt

Daniel Bystedt commented

2019-12-26 00:08:51 +01:00

I get the same results with the scene that Davidmikucki provided. The issue seems to be directly related to soft shadows in Eevees render settings and also sss translucency as mentioned above.

The lighting seems a bit like a corner case scenario though. The SSS is extremely low. Using realtime rendering solutions will always present certain artifacts that needs to be fixed/hidden in my experience.

Here are some tweaks that can help with your rendering

I get the same results with the scene that Davidmikucki provided. The issue seems to be directly related to soft shadows in Eevees render settings and also sss translucency as mentioned above. The lighting seems a bit like a corner case scenario though. The SSS is extremely low. Using realtime rendering solutions will always present certain artifacts that needs to be fixed/hidden in my experience. Here are some tweaks that can help with your rendering ![sss artifacts.jpg](https://archive.blender.org/developer/F8244510/sss_artifacts.jpg)

David Mikucki commented

2019-12-26 00:45:02 +01:00

This is super helpful, thanks! I'm not sure I understand what "SSS multed by 100" means, though? Could you elaborate?

I totally understand that realtime SSS, especially translucent SSS, is always going to have issues. But I don't know if I'd call this a corner case. These are pretty much the most realistic settings I've found for emulating skin SSS and I get it pretty much any time I try to set up dramatic lighting.

This is super helpful, thanks! I'm not sure I understand what "SSS multed by 100" means, though? Could you elaborate? I totally understand that realtime SSS, especially translucent SSS, is always going to have issues. But I don't know if I'd call this a corner case. These are pretty much the most realistic settings I've found for emulating skin SSS and I get it pretty much any time I try to set up dramatic lighting.

Germano Cavalcante commented

2019-12-27 14:58:22 +01:00

Added subscribers: @fclem, @mano-wii

Germano Cavalcante commented

2019-12-27 14:58:22 +01:00

@fclem, is this a known limitation or a bug?
Not sure if I correctly understand the limitations described here: https://docs.blender.org/manual/en/latest/render/eevee/limitations.html#eevee-limitations-sss

@fclem, is this a known limitation or a bug? Not sure if I correctly understand the limitations described here: https://docs.blender.org/manual/en/latest/render/eevee/limitations.html#eevee-limitations-sss

Daniel Bystedt commented

2019-12-27 15:30:18 +01:00

In #72695#837797, @davidmikucki wrote:
This is super helpful, thanks! I'm not sure I understand what "SSS multed by 100" means, though? Could you elaborate?

I totally understand that realtime SSS, especially translucent SSS, is always going to have issues. But I don't know if I'd call this a corner case. These are pretty much the most realistic settings I've found for emulating skin SSS and I get it pretty much any time I try to set up dramatic lighting.

Sorry about my shorthand. By multing sss I mean that I multiply the scale of the SSS by 100. The sss has a larger radius in the edit that I made

> In #72695#837797, @davidmikucki wrote: > This is super helpful, thanks! I'm not sure I understand what "SSS multed by 100" means, though? Could you elaborate? > > I totally understand that realtime SSS, especially translucent SSS, is always going to have issues. But I don't know if I'd call this a corner case. These are pretty much the most realistic settings I've found for emulating skin SSS and I get it pretty much any time I try to set up dramatic lighting. Sorry about my shorthand. By multing sss I mean that I multiply the scale of the SSS by 100. The sss has a larger radius in the edit that I made

David Mikucki commented

2019-12-27 18:43:32 +01:00

Ah. Thanks. Yeah, you're right, Scaling the SSS up has an effect. It also seems to be the case that I would expect the SSS slider to affect the opacity of the SSS—but it actually seems to be a scale multiplier. So to get the scale right, then turn down the effect, I have to duplicate my node setup, turn off SSS on the duplicate mat, and then combine them with a mixer. This is giving decent results.

Maybe this isn't a bug? I'm not entirely sure at this point. Please feel free to close if it's just my misunderstanding of how to use SSS.

Ah. Thanks. Yeah, you're right, Scaling the SSS up has an effect. It also seems to be the case that I would expect the SSS slider to affect the opacity of the SSS—but it actually seems to be a scale multiplier. So to get the scale right, then turn down the effect, I have to duplicate my node setup, turn off SSS on the duplicate mat, and then combine them with a mixer. This is giving decent results. Maybe this isn't a bug? I'm not entirely sure at this point. Please feel free to close if it's just my misunderstanding of how to use SSS.

Germano Cavalcante commented

2020-01-09 21:49:27 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Clément Foucault commented

2020-01-15 20:54:31 +01:00

It is an artifact of using the shadowmap to create translucency effect. I already tried to mitigate the issue so I'm not sure I can really do much more.

I don't like adding user side hacks but this might be an instance where it is really needed.

It is an artifact of using the shadowmap to create translucency effect. I already tried to mitigate the issue so I'm not sure I can really do much more. I don't like adding user side hacks but this might be an instance where it is really needed.

Philipp Oeser commented

2020-01-15 21:12:55 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2020-01-15 21:12:55 +01:00

In #72695#850369, @fclem wrote:
I already tried to mitigate the issue so I'm not sure I can really do much more.

Just for reference: I think it was {131ac2ec82}?

> In #72695#850369, @fclem wrote: >I already tried to mitigate the issue so I'm not sure I can really do much more. Just for reference: I think it was {131ac2ec82}?

Aleksandr commented

2020-07-12 10:31:25 +02:00

Added subscriber: @viadvena

Aleksandr commented

2020-07-12 10:31:25 +02:00

System Information
Operating system: Linux-4.15.0-109-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21

Blender Version
Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: 239fbf7d93
Worked: (newest version of Blender that worked as expected)

Similar issue... Translusency completely unusable for me.

SSS_Bug.blend

**System Information** Operating system: Linux-4.15.0-109-generic-x86_64-with-debian-buster-sid 64 Bits Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21 **Blender Version** Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: `239fbf7d93` Worked: (newest version of Blender that worked as expected) Similar issue... Translusency completely unusable for me. ![1.png](https://archive.blender.org/developer/F8688459/1.png) [SSS_Bug.blend](https://archive.blender.org/developer/F8688461/SSS_Bug.blend)

Philipp Oeser removed the

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Eeevee SSS Artifacts with Subsurface Translucency on #72695