Marbling effect on Eevee and subsurface scattering... #70249

New Issue

Lawrence Teng · 2019-09-25T17:55:06+02:00

Lawrence Teng commented

2019-09-25 17:55:06 +02:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 1070 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.60

Blender Version
Broken: version: 2.81 (sub 12), branch: master, commit date: 2019-09-25 13:57, hash: f8da7218be

Short description of error
Eevee backlight causes marbling light effects...with subsurface scattering

Exact steps for others to reproduce the error
Created Suzanne model, added backlight. (included screen shot and test file)
SUZANNE_eevee_bklight.blend

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: GeForce GTX 1070 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.60 **Blender Version** Broken: version: 2.81 (sub 12), branch: master, commit date: 2019-09-25 13:57, hash: `f8da7218be` **Short description of error** Eevee backlight causes marbling light effects...with subsurface scattering **Exact steps for others to reproduce the error** Created Suzanne model, added backlight. (included screen shot and test file) [SUZANNE_eevee_bklight.blend](https://archive.blender.org/developer/F7774753/SUZANNE_eevee_bklight.blend) ![suzanne_backlight.jpg](https://archive.blender.org/developer/F7774751/suzanne_backlight.jpg)

Lawrence Teng commented

2019-09-25 17:55:06 +02:00

Added subscriber: @Lteng

blender-admin commented

2019-09-25 17:55:06 +02:00

#69827 was marked as duplicate of this issue

Lawrence Teng commented

2019-09-25 17:59:44 +02:00

I tested the version in 9-13-2019 as well and the marbling is also there. Not sure about earlier september versions.
I noticed also that changing the 'count' in the cascaded shadow map changes the marbling effect. (video capture included):
Blender_ [C__Users_Graphics 4_Downloads_Wip_SUZANNE_eevee_bklight.blend] 2019-09-25 08-57-47.mp4

I tested the version in 9-13-2019 as well and the marbling is also there. Not sure about earlier september versions. I noticed also that changing the 'count' in the cascaded shadow map changes the marbling effect. (video capture included): [Blender_ [C__Users_Graphics 4_Downloads_Wip_SUZANNE_eevee_bklight.blend] 2019-09-25 08-57-47.mp4](https://archive.blender.org/developer/F7774759/Blender___C__Users_Graphics_4_Downloads_Wip_SUZANNE_eevee_bklight.blend__2019-09-25_08-57-47.mp4)

Philipp Oeser commented

2019-09-25 20:10:23 +02:00

Added subscribers: @fclem, @lichtwerk

Clément Foucault was assigned by Philipp Oeser

2019-09-25 20:10:23 +02:00

Philipp Oeser commented

2019-09-25 20:10:23 +02:00

This is due to d8aaf25c23.

There are some things mentioned in D5659: Eevee: Shadow map refactor regarding SSS..
There is also more information here https://wiki.blender.org/wiki/Reference/Release_Notes/2.81/Eevee
That all being said, just opening your file in 2.81 after the shadow refactor will not give you the same results.

However, by tweaking some settings, you should be able to get comparable (if not better) results.

I think the main point is to enable Soft Shadows under Properties Editor > Render Properties > Shadows (this was previously a per light setting)
upping viewport samples Properties Editor > Render Properties > Sampling also helps

Dont think this counts as a bug, but will let @fclem close...

This is due to d8aaf25c23. There are some things mentioned in [D5659: Eevee: Shadow map refactor](https://archive.blender.org/developer/D5659) regarding SSS.. There is also more information here https://wiki.blender.org/wiki/Reference/Release_Notes/2.81/Eevee That all being said, just opening your file in 2.81 after the shadow refactor will not give you the same results. However, by tweaking some settings, you should be able to get comparable (if not better) results. - I think the main point is to enable `Soft Shadows` under `Properties Editor` > `Render Properties` > `Shadows` (this was previously a per light setting) - upping viewport samples `Properties Editor` > `Render Properties` > `Sampling` also helps Dont think this counts as a bug, but will let @fclem close...

Jean Da Costa commented

2019-09-25 20:17:50 +02:00

Added subscriber: @jeacom

Jean Da Costa commented

2019-09-25 20:17:50 +02:00

Bug or not, this is an undesirable behavior that makes SSS quality awful, to the point of unusable, this needs fix.

Philipp Oeser commented

2019-09-25 20:43:19 +02:00

@jeacom : have you tried enabling Soft Shadows and setting Viewport Samples to 64 upwards?
(this seems to have no marble artifacts for me -- can you show where this is still awful?)

I agree though that translucency looks different from before [distribution seems to be different, cannot be as soft as before?], maybe @fclem can comment on that...

@jeacom : have you tried enabling `Soft Shadows` and setting Viewport Samples to 64 upwards? (this seems to have no marble artifacts for me -- can you show where this is still awful?) I agree though that translucency looks different from before [distribution seems to be different, cannot be as soft as before?], maybe @fclem can comment on that...

SecuoyaEx commented

2019-09-26 15:57:49 +02:00

Added subscriber: @SecuoyaEx

SecuoyaEx commented

2019-09-26 15:57:49 +02:00

All those things may make it less noticeable but it doesn't solve it. More samples don't make it converge either.
Here's an example with with big radius, higher res shadows, soft shadows, lots of sss samples and viewport/render samples, high bitdepth, etc. Still visible

Crucially, if you turn off shadows for a particular light, SSS translucency will disappear.

There's at least one improvement. With VSM shadows in the past, the middle of things would get darker, like the ear. Now it's closer to Cycles. In any case, I think the line needs fixing, otherwise translucency is almost useless

All those things may make it less noticeable but it doesn't solve it. More samples don't make it converge either. Here's an example with with big radius, higher res shadows, soft shadows, lots of sss samples and viewport/render samples, high bitdepth, etc. Still visible ![image.png](https://archive.blender.org/developer/F7775842/image.png) Crucially, if you turn off shadows for a particular light, SSS translucency will disappear. There's at least one improvement. With VSM shadows in the past, the middle of things would get darker, like the ear. Now it's closer to Cycles. In any case, I think the line needs fixing, otherwise translucency is almost useless

Jean Da Costa commented

2019-09-26 16:40:57 +02:00

@lichtwerk enabling soft shadows or upping samples only seems to smear out but not remove this weird line.

2048 samples, soft shadows enabled and the problem is still there:

@lichtwerk enabling soft shadows or upping samples only seems to smear out but not remove this weird line. 2048 samples, soft shadows enabled and the problem is still there: ![image.png](https://archive.blender.org/developer/F7775887/image.png)

Bent Hillerkus commented

2019-09-26 17:11:17 +02:00

Added subscriber: @bent

Philipp Oeser commented

2019-09-26 22:29:32 +02:00

Thx for getting back now I actually get it better what is meant by 'marbling'.
Tbh, I am not sure what the origins of these are [or how to get rid of them], I think @fclem has to chime in here...

Thx for getting back now I actually get it better what is meant by 'marbling'. Tbh, I am not sure what the origins of these are [or how to get rid of them], I think @fclem has to chime in here...

Jean Da Costa commented

2019-09-27 01:23:58 +02:00

I am convinced that it was caused by D5659 might be some biasing issue.

I am convinced that it was caused by [D5659](https://archive.blender.org/developer/D5659) might be some biasing issue.

Clément Foucault commented

2019-09-28 00:58:36 +02:00

It is caused by my refactor yes.

This is a side effect of having biased shadow maps. Before they were smoothed but I remove the smoothness properties.

A better ways would be to introduce a corrective bias to make it match perfectly the depth that is supposed to be in the shadow map.

It is caused by my refactor yes. This is a side effect of having biased shadow maps. Before they were smoothed but I remove the smoothness properties. A better ways would be to introduce a corrective bias to make it match perfectly the depth that is supposed to be in the shadow map.

blender-admin commented

2019-10-16 18:53:19 +02:00

This issue was referenced by 131ac2ec82

This issue was referenced by 131ac2ec82b9e810dd6e0153009a71276b6d6f13

Clément Foucault commented

2019-10-16 19:03:58 +02:00

Changed status from 'Open' to: 'Resolved'

Clément Foucault closed this issue

2019-10-16 19:03:58 +02:00

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Marbling effect on Eevee and subsurface scattering... #70249