EEVEE shadow from sun on incorrect face #71661

New Issue

Neith Zaldrizes · 2019-11-18T18:03:13+01:00

Neith Zaldrizes commented

2019-11-18 18:03:13 +01:00

System Information
Operating system: Windows 10
Graphics card: gtx 1070

Blender Version
Broken: 2.81,eba4a4bd73ba
Worked: (optional)

Short description of error

Exact steps for others to reproduce the error
Make a plane, extrude edge downwards put sun next to it and above the plane pointing towards the edge. The new plane that was extruded from edge will cast shadow on plane above it which makes absolutely no sense and is very difficult/impossible to fix/mask with trickery so I am reporting it as a bug. Here is the blend file for example:

shadowproblem.blend

**System Information** Operating system: Windows 10 Graphics card: gtx 1070 **Blender Version** Broken: 2.81,eba4a4bd73ba Worked: (optional) **Short description of error** **Exact steps for others to reproduce the error** Make a plane, extrude edge downwards put sun next to it and above the plane pointing towards the edge. The new plane that was extruded from edge will cast shadow on plane above it which makes absolutely no sense and is very difficult/impossible to fix/mask with trickery so I am reporting it as a bug. Here is the blend file for example: [shadowproblem.blend](https://archive.blender.org/developer/F8131209/shadowproblem.blend)

Neith Zaldrizes commented

2019-11-18 18:03:13 +01:00

Added subscriber: @zaldrizes

Philipp Oeser commented

2019-11-19 11:52:38 +01:00

Added subscribers: @fclem, @lichtwerk

Philipp Oeser commented

2019-11-19 11:52:38 +01:00

Would assume this is not a bug, but some limitation of cascaded shadow maps?

https://docs.blender.org/manual/en/dev/render/eevee/lighting.html#cascaded-shadow-map

Tweaking the settings [lowering suns max distance for example, playing with distribution, ..., also eevee shadow Cascade Size to maximum 4096px] helps making the artefacts less apparent.
(not seeing the Bias really having any effect here, so I am a bit on shaky ground as well)

Not being 100% sure, I will let @fclem decide...
(I think what would be good is document the known limitations/artefacts with example images in the manual, so we can come back to these if neccessary...)

Would assume this is not a bug, but some limitation of cascaded shadow maps? https://docs.blender.org/manual/en/dev/render/eevee/lighting.html#cascaded-shadow-map Tweaking the settings [lowering suns `max distance` for example, playing with `distribution`, ..., also eevee shadow `Cascade Size` to maximum 4096px] helps making the artefacts less apparent. (not seeing the Bias really having any effect here, so I am a bit on shaky ground as well) Not being 100% sure, I will let @fclem decide... (I think what would be good is document the known limitations/artefacts with example images in the manual, so we can come back to these if neccessary...)

Clément Foucault commented

2019-11-19 14:27:54 +01:00

The artifact is caused by shadowmap aliasing (low res). This is the only case where you want to increase the shadow bias.

But the real bug here is that the bias is multiplied by a really small value. If you type a really high value the bias is visible. I don't know if this is to be considered something critical to be changed prior release.

The bias is also dependent on the scale of the scene so I think there is some improvement to be made here.

The artifact is caused by shadowmap aliasing (low res). This is the only case where you want to increase the shadow bias. But the real bug here is that the bias is multiplied by a really small value. If you type a really high value the bias is visible. I don't know if this is to be considered something critical to be changed prior release. The bias is also dependent on the scale of the scene so I think there is some improvement to be made here.

Philipp Oeser commented

2019-11-19 15:18:38 +01:00

Added subscribers: @dfelinto, @jesterking

Philipp Oeser commented

2019-11-19 15:18:38 +01:00

I don't know if this is to be considered something critical to be changed prior release.

Tbh, I cannot judge how severe this is.
Maybe you should chat with @jesterking , @dfelinto ?

> I don't know if this is to be considered something critical to be changed prior release. Tbh, I cannot judge how severe this is. Maybe you should chat with @jesterking , @dfelinto ?

blender-admin commented

2020-02-14 12:17:06 +01:00

This issue was referenced by 31ad86884c

This issue was referenced by 31ad86884cb1b9257f8958cd50942e76aefbd705

Clément Foucault commented

2020-02-14 12:27:24 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Clément Foucault closed this issue

2020-02-14 12:27:24 +01:00

Clément Foucault self-assigned this 2020-02-14 12:27:24 +01:00

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EEVEE shadow from sun on incorrect face #71661