Possible errors introduced in the new SSS implementation (in the days after it was committed) #47356

New Issue

Adam Friesen · 2016-02-07T21:27:14+01:00

Adam Friesen commented

2016-02-07 21:27:14 +01:00

System Information
Win10 64 bit, an ATI 7xxx GPU, 24 gigs RAM, third gen i7 processor

Blender Version
Broken: hash 578f70f
Worked: hash da7ddb6

Short description of error
Very recent tweaks to the new SSS model seems to have introduces what appears to be pronounced steps in the terminator when the radius has different values for the red, green, and blue channels. This did not exist in the initial implementation and is far harsher than simple cubic scattering. This being with CPU rendering by the way).

Exact steps for others to reproduce the error
Download the .blend file and render, here's an image of what to expect depending on the builds (I will also note that there were no settings whatsoever that were changed).

.blend
SSScube.blend

I know the implementation still has a WIP component to it, but I do think the recent tweaks may have made it less correct instead of more.

**System Information** Win10 64 bit, an ATI 7xxx GPU, 24 gigs RAM, third gen i7 processor **Blender Version** Broken: hash 578f70f Worked: hash da7ddb6 **Short description of error** Very recent tweaks to the new SSS model seems to have introduces what appears to be pronounced steps in the terminator when the radius has different values for the red, green, and blue channels. This did not exist in the initial implementation and is far harsher than simple cubic scattering. This being with CPU rendering by the way). **Exact steps for others to reproduce the error** Download the .blend file and render, here's an image of what to expect depending on the builds (I will also note that there were no settings whatsoever that were changed). ![SSSerrors.jpg](https://archive.blender.org/developer/F280740/SSSerrors.jpg) **.blend** [SSScube.blend](https://archive.blender.org/developer/F280742/SSScube.blend) I know the implementation still has a WIP component to it, but I do think the recent tweaks may have made it less correct instead of more.

Adam Friesen commented

2016-02-07 21:27:14 +01:00

Changed status to: 'Open'

Adam Friesen commented

2016-02-07 21:27:14 +01:00

Added subscriber: @Ace_Dragon

Adam Friesen commented

2016-02-07 21:35:55 +01:00

Here's a better illustration of the terminator error (with a lot more samples together with a curve adjustment to show it is not a product of undersampling)

You can practically see lines in the falloff, I don't think that's supposed to happen.

Here's a better illustration of the terminator error (with a lot more samples together with a curve adjustment to show it is not a product of undersampling) ![SSSerrors2.jpg](https://archive.blender.org/developer/F280745/SSSerrors2.jpg) You can practically see lines in the falloff, I don't think that's supposed to happen.

Sergey Sharybin self-assigned this 2016-02-08 13:53:20 +01:00

blender-admin commented

2016-02-08 14:54:11 +01:00

This issue was referenced by dae8326d1e

This issue was referenced by dae8326d1e98632be42e525011c061d46c1d0e2a

Sergey Sharybin commented

2016-02-08 14:54:58 +01:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2016-02-08 14:54:58 +01:00

blender-admin commented

2016-02-11 13:07:36 +01:00

This issue was referenced by blender/cycles@cc8180a24d

This issue was referenced by blender/cycles@cc8180a24dbad4fb5ec4ec4dcd4cd4e8badc174e

Sergey Sharybin commented

2016-02-13 13:31:46 +01:00

Please refer to commit notes for 69dc0c3. The original patch for this report wasn't correct and Burley is not expected to be that much smoother actually for the same mean free path distance.

Please refer to commit notes for 69dc0c3. The original patch for this report wasn't correct and Burley is not expected to be that much smoother actually for the same mean free path distance.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Possible errors introduced in the new SSS implementation (in the days after it was committed) #47356