Regression: Light leaking when using normal maps with Multiscatter GGX #96576

New Issue

Human193 · 2022-03-17T22:02:22+01:00

Human193 commented

2022-03-17 22:02:22 +01:00

System Information
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 511.79

Blender Version
Broken: version: 3.1.0, branch: master, commit date: 2022-03-08 18:16, hash: c77597cd0e
Worked: 3.0.1
Caused by ae44070341

Short description of error
In Cycles light seems to go through walls when using Princibled BSDF with a normal map or bump map (can also be a procedural texture) if Multiscatter GGX is used. It doesn't matter in which direction the normals are facing. It happens with both GPU and CPU rendering. The roughness has to be above 0.075

There is a bright lamp inside the cube:
Multiscatter GGX in Blender 3.1:

GGX in Blender 3.1:

Multiscatter GGX in Blender 3.0.1:

Exact steps for others to reproduce the error
Create a cube with a lamp inside. Make a new shader with a Princibled BSDF with a roughness above 0.075 and with a normal map or bump map with any texture.

normal map light leak.blend

**System Information** Operating system: Windows-10-10.0.19044-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 511.79 **Blender Version** Broken: version: 3.1.0, branch: master, commit date: 2022-03-08 18:16, hash: `c77597cd0e` Worked: 3.0.1 Caused by ae44070341 **Short description of error** In Cycles light seems to go through walls when using Princibled BSDF with a normal map or bump map (can also be a procedural texture) if Multiscatter GGX is used. It doesn't matter in which direction the normals are facing. It happens with both GPU and CPU rendering. The roughness has to be above 0.075 There is a bright lamp inside the cube: Multiscatter GGX in Blender 3.1: ![Screenshot 2022-03-15 180227.png](https://archive.blender.org/developer/F12932247/Screenshot_2022-03-15_180227.png) GGX in Blender 3.1: ![Screenshot 2022-03-15 180238.png](https://archive.blender.org/developer/F12932250/Screenshot_2022-03-15_180238.png) Multiscatter GGX in Blender 3.0.1: ![Screenshot 2022-03-15 180651.png](https://archive.blender.org/developer/F12932252/Screenshot_2022-03-15_180651.png) **Exact steps for others to reproduce the error** Create a cube with a lamp inside. Make a new shader with a Princibled BSDF with a roughness above 0.075 and with a normal map or bump map with any texture. [normal map light leak.blend](https://archive.blender.org/developer/F12932276/normal_map_light_leak.blend)

Human193 commented

2022-03-17 22:02:23 +01:00

Added subscriber: @RandomGuy

Alaska commented

2022-03-17 22:29:28 +01:00

Added subscribers: @brecht, @Alaska

Alaska commented

2022-03-17 22:29:28 +01:00

I can confirm this issue with the setup below.

The issue was introduced in ae44070341. CC @brecht

System Information
Operating system: Linux-5.16.0-3-amd64-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54
Blender version: 3.2.0 Alpha, branch: master, commit date: 2022-03-17 16:52, hash: 7fed4c06c2

I can confirm this issue with the setup below. The issue was introduced in ae44070341. CC @brecht **System Information** Operating system: Linux-5.16.0-3-amd64-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54 Blender version: 3.2.0 Alpha, branch: master, commit date: 2022-03-17 16:52, hash: `7fed4c06c2`

Richard Antalik commented

2022-03-17 22:44:13 +01:00

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

Pratik Borhade commented

2022-03-18 05:18:42 +01:00

Added subscriber: @PratikPB2123

Connor M. Denning commented

2022-03-22 04:39:35 +01:00

Added subscriber: @Connor-Denning

Connor M. Denning commented

2022-03-22 04:39:35 +01:00

idk if related but in some test renders I did recently with like 256 bounces or something I thought it looked overly bright for having shaders that shouldn't be emitting more then possible I had one that wasn't even fixing that it looked to bright to me. If I can reproduce it I'll post it most likely I have another report in the works though so might take a few days. But I'm really not getting why there being a .blend that test just about every thing like this in one go hasn't been some we have for each blender release that would fix things like this from getting missed in optimizations.

Connor M. Denning commented

2022-03-22 04:42:43 +01:00

Removed subscriber: @Connor-Denning

Connor M. Denning commented

2022-03-22 04:43:05 +01:00

Added subscriber: @Connor-Denning

Alaska commented

2022-03-22 05:01:14 +01:00

In #96576#1327321, @Connor-Denning wrote:
idk if related but in some test renders I did recently with like 256 bounces or something I thought it looked overly bright for having shaders that shouldn't be emitting more then possible I had one that wasn't even fixing that it looked to bright to me. If I can reproduce it I'll post it most likely I have another report in the works though so might take a few days. But I'm really not getting why there being a .blend that test just about every thing like this in one go hasn't been some we have for each blender release that would fix things like this from getting missed in optimizations.

There was a issue reported recently of the Principled BSDF reflecting more light than it theoretically should in the specular part of the material when the material base colour was above a certain threshold. This might of been what you were experiencing? If so, it has already been reported and it is not considered a "bug". Apparently this is because the Principled BSDF is based on a shader from a white paper from Disney. And the shader proposed by Disney has this exact same issue. Cycles replicates this issue to ensure compatibility between other software using the same shader model (which also most likely have that issue).

> In #96576#1327321, @Connor-Denning wrote: > idk if related but in some test renders I did recently with like 256 bounces or something I thought it looked overly bright for having shaders that shouldn't be emitting more then possible I had one that wasn't even fixing that it looked to bright to me. If I can reproduce it I'll post it most likely I have another report in the works though so might take a few days. But I'm really not getting why there being a .blend that test just about every thing like this in one go hasn't been some we have for each blender release that would fix things like this from getting missed in optimizations. There was a issue reported recently of the Principled BSDF reflecting more light than it theoretically should in the specular part of the material when the material base colour was above a certain threshold. This might of been what you were experiencing? If so, it has already been reported and it is not considered a "bug". Apparently this is because the Principled BSDF is based on a shader from a white paper from Disney. And the shader proposed by Disney has this exact same issue. Cycles replicates this issue to ensure compatibility between other software using the same shader model (which also most likely have that issue).

Philipp Oeser changed title from ~~Light leaking when using normal maps with Multiscatter GGX~~ to Regression: Light leaking when using normal maps with Multiscatter GGX

2022-03-22 16:04:36 +01:00

Connor M. Denning commented

2022-03-23 06:48:51 +01:00

In #96576#1327386, @Alaska wrote:

In #96576#1327321, @Connor-Denning wrote:
idk if related but in some test renders I did recently with like 256 bounces or something I thought it looked overly bright for having shaders that shouldn't be emitting more then possible I had one that wasn't even fixing that it looked to bright to me. If I can reproduce it I'll post it most likely I have another report in the works though so might take a few days. But I'm really not getting why there being a .blend that test just about every thing like this in one go hasn't been some we have for each blender release that would fix things like this from getting missed in optimizations.

There was a issue reported recently of the Principled BSDF reflecting more light than it theoretically should in the specular part of the material when the material base colour was above a certain threshold. This might of been what you were experiencing? If so, it has already been reported and it is not considered a "bug". Apparently this is because the Principled BSDF is based on a shader from a white paper from Disney. And the shader proposed by Disney has this exact same issue. Cycles replicates this issue to ensure compatibility between other software using the same shader model (which also most likely have that issue).

Still it would seem like it should have a checkmark to toggle weather or not it dose that.

> In #96576#1327386, @Alaska wrote: >> In #96576#1327321, @Connor-Denning wrote: >> idk if related but in some test renders I did recently with like 256 bounces or something I thought it looked overly bright for having shaders that shouldn't be emitting more then possible I had one that wasn't even fixing that it looked to bright to me. If I can reproduce it I'll post it most likely I have another report in the works though so might take a few days. But I'm really not getting why there being a .blend that test just about every thing like this in one go hasn't been some we have for each blender release that would fix things like this from getting missed in optimizations. > > There was a issue reported recently of the Principled BSDF reflecting more light than it theoretically should in the specular part of the material when the material base colour was above a certain threshold. This might of been what you were experiencing? If so, it has already been reported and it is not considered a "bug". Apparently this is because the Principled BSDF is based on a shader from a white paper from Disney. And the shader proposed by Disney has this exact same issue. Cycles replicates this issue to ensure compatibility between other software using the same shader model (which also most likely have that issue). Still it would seem like it should have a checkmark to toggle weather or not it dose that.

Lt Knb commented

2022-03-25 14:30:21 +01:00

Added subscriber: @Lt-Knb