Cycles Transparent Shading BUG #92450

New Issue

baoyu · 2021-10-24T14:50:47+02:00

baoyu commented

2021-10-24 14:50:47 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-10-23 20:02, hash: 8c21667f3c
Worked: (newest version of Blender that worked as expected)

Short description of error
When Object A with transparent shader intersecting Object B with MultiscatterGGX Glass shader or GGX shader+Volume Absorption, will cause artifacts.

The glass base mesh (mentioned as Object B) has three shading combination:
①GGX Glass shader at 0 roughness + Volume Absorption
②Multiscatter GGX Glass shader at 0 roughness + Volume Absorption
③Multiscatter GGX Glass shader at more than 0 roughness
All three combination will cause the artifact.
The following pic is rendered with all light path set to 64 and quite high iteration samples.

Exact steps for others to reproduce the error
Please open the providing blend file to reproduce.
Transparent Shading BUG.blend

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-10-23 20:02, hash: `8c21667f3c` Worked: (newest version of Blender that worked as expected) **Short description of error** When ***Object A with transparent shader*** intersecting ***Object B with MultiscatterGGX Glass shader or GGX shader+Volume Absorption***, will cause artifacts. The glass base mesh (mentioned as Object B) has three shading combination: ①GGX Glass shader at 0 roughness + Volume Absorption ②Multiscatter GGX Glass shader at 0 roughness + Volume Absorption ③Multiscatter GGX Glass shader at **more than** 0 roughness All three combination will cause the artifact. The following pic is rendered with all light path set to 64 and quite high iteration samples. ![image.png](https://archive.blender.org/developer/F11466769/image.png) ![image.png](https://archive.blender.org/developer/F11466802/image.png) **Exact steps for others to reproduce the error** Please open the providing blend file to reproduce. [Transparent Shading BUG.blend](https://archive.blender.org/developer/F11466819/Transparent_Shading_BUG.blend)

baoyu commented

2021-10-24 14:50:47 +02:00

Added subscriber: @baoyu

baoyu commented

2021-10-24 14:51:56 +02:00

Added subscriber: @brecht

baoyu commented

2021-10-24 15:16:29 +02:00

Added subscriber: @Sergey

Mikhail Matrosov commented

2021-10-24 20:06:37 +02:00

Added subscriber: @ktdfly

Richard Antalik commented

2021-10-26 06:40:26 +02:00

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

baoyu commented

2021-10-26 09:57:17 +02:00

It remains me of another annoying bug which hasn't been solved yet.
https://developer.blender.org/T85259

It remains me of another annoying bug which hasn't been solved yet. https://developer.blender.org/T85259 ![image.png](https://archive.blender.org/developer/F11516929/image.png)

baoyu commented

2021-10-26 11:13:45 +02:00

This transparent shading bug makes it unable to render decals over glassware using cycles.

This transparent shading bug makes it unable to render **decals over glassware** using cycles.

Brecht Van Lommel commented

2021-11-03 22:08:25 +01:00

This appears to be caused by our trick to skip the shade_surface kernel if we know it has no emission or shadow transparency. We assume the throughput is the same in intersect_closest, but with shade_volume in between that is not the case.

This appears to be caused by our trick to skip the `shade_surface` kernel if we know it has no emission or shadow transparency. We assume the throughput is the same in `intersect_closest`, but with `shade_volume` in between that is not the case.

blender-admin commented

2021-11-04 16:39:49 +01:00

This issue was referenced by blender/cycles@abae29fbbd

This issue was referenced by blender/cycles@abae29fbbd5583ebcb42d6121560659b2bb71201

blender-admin commented

2021-11-04 16:39:49 +01:00

This issue was referenced by ffe115d1a8

This issue was referenced by ffe115d1a8f625bb5a6b72616fa2f955448869ff

Brecht Van Lommel commented

2021-11-04 16:48:11 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Brecht Van Lommel closed this issue

2021-11-04 16:48:11 +01:00

Brecht Van Lommel self-assigned this 2021-11-04 16:48:11 +01:00

blender-admin commented

2021-11-04 16:50:41 +01:00

This issue was referenced by None@62742

baoyu commented

2021-11-06 00:01:48 +01:00

Tested on build

version: 3.1.0 Alpha, branch: master
commit date: 2021-11-04 21:35
hash: 3364a5bea6
build date: 2021-11-05, 01:00:16

Quite happy to see that the volume + transparent bug has been solved.
While the Multiscatter GGX + transparent scenario still gives the wrong result.

Tested on build >version: 3.1.0 Alpha, branch: master >commit date: 2021-11-04 21:35 >hash: 3364a5bea6c9 >build date: 2021-11-05, 01:00:16 Quite happy to see that the volume + transparent bug has been solved. While the Multiscatter GGX + transparent scenario still gives the wrong result. ![image.png](https://archive.blender.org/developer/F11738838/image.png)

Fernando Alcala commented

2021-11-13 20:53:00 +01:00

Added subscriber: @Fernando-Alcala

Fernando Alcala commented

2021-11-13 20:53:00 +01:00

You should create another report for the rough one

baoyu commented

2021-11-13 22:31:00 +01:00

In #92450#1253376, @Fernando-Alcala wrote:
You should create another report for the rough one

This is the new thread.
https://developer.blender.org/T93068

> In #92450#1253376, @Fernando-Alcala wrote: > You should create another report for the rough one This is the new thread. https://developer.blender.org/T93068

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Cycles Transparent Shading BUG #92450