Maniphest T96576

Regression: Light leaking when using normal maps with Multiscatter GGX
Closed, ResolvedBUG

Assigned To
Lukas Stockner (lukasstockner97)
Authored By
Human193 (RandomGuy)
Mar 17 2022, 10:02 PM
Tags
  • BF Blender
  • Render & Cycles
Subscribers
Alaska (Alaska)
Brecht Van Lommel (brecht)
Connor M. Denning (ConMan)
Human193 (RandomGuy)
Lt Knb (Lt-knb)
Pratik Borhade (PratikPB2123)
thin soldier (thinsoldier)

Description

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: rBc77597cd0e15
Worked: 3.0.1
Caused by rBae4407034114: Cycles: explicitly skip self-intersection

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.

Revisions and Commits

rB Blender

Related Objects

Mentioned In
P2839 3.1 R
Mentioned Here
rBae4407034114: Cycles: explicitly skip self-intersection

Event Timeline

Human193 (RandomGuy) created this task.Mar 17 2022, 10:02 PM
Alaska (Alaska) added subscribers: Brecht Van Lommel (brecht), Alaska (Alaska).Mar 17 2022, 10:29 PM

I can confirm this issue with the setup below.

The issue was introduced in rBae4407034114: Cycles: explicitly skip self-intersection. CC @Brecht Van Lommel (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: rB7fed4c06c2ff

Alaska (Alaska) updated the task description.Mar 17 2022, 10:29 PM
Richard Antalik (ISS) changed the task status from Needs Triage to Confirmed.Mar 17 2022, 10:44 PM
Richard Antalik (ISS) added a project: Render & Cycles.
Alaska (Alaska) changed the subtype of this task from "Report" to "Bug".Mar 17 2022, 11:42 PM
Pratik Borhade (PratikPB2123) triaged this task as High priority.Mar 18 2022, 5:18 AM
Pratik Borhade (PratikPB2123) added a subscriber: Pratik Borhade (PratikPB2123).
Pratik Borhade (PratikPB2123) mentioned this in P2839 3.1 R.Mar 20 2022, 12:20 PM
Connor M. Denning (ConMan) added a subscriber: Connor M. Denning (ConMan).EditedMar 22 2022, 4:39 AM

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 (ConMan) removed a subscriber: Connor M. Denning (ConMan).Mar 22 2022, 4:42 AM
Connor M. Denning (ConMan) added a subscriber: Connor M. Denning (ConMan).
Alaska (Alaska) added a comment.Mar 22 2022, 5:01 AM
In T96576#1327321, @Connor M. Denning (ConMan) 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 (lichtwerk) renamed this task from Light leaking when using normal maps with Multiscatter GGX to Regression: Light leaking when using normal maps with Multiscatter GGX.Mar 22 2022, 4:04 PM
Connor M. Denning (ConMan) added a comment.Mar 23 2022, 6:48 AM
In T96576#1327386, @Alaska (Alaska) wrote:
In T96576#1327321, @Connor M. Denning (ConMan) 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 (Lt-knb) added a subscriber: Lt Knb (Lt-knb).Mar 25 2022, 2:30 PM
thin soldier (thinsoldier) added a subscriber: thin soldier (thinsoldier).Apr 27 2022, 2:02 AM
Lukas Stockner (lukasstockner97) claimed this task.Apr 30 2022, 1:51 PM
Lukas Stockner (lukasstockner97) closed this task as Resolved by committing rBac88123e29d4: Fix T96576: Light leaking when using normal maps with Multiscatter GGX.Apr 30 2022, 1:56 PM
Lukas Stockner (lukasstockner97) added a commit: rBac88123e29d4: Fix T96576: Light leaking when using normal maps with Multiscatter GGX.