Partly transparent objects appear to glow in the dark when HDRI environment lighting is present (BVH2/Some GPU rendering backends) #95462

Closed
opened 2022-02-03 03:47:25 +01:00 by Stellarator Tokamak · 15 comments

System Information
Operating system: Windows 10
Graphics card: NVIDIA GeForce RTX 2080

Blender Version
Broken: 3.0.1, branch: master, date: 2022-01-25 (latest version on blender.org)

Worked: Any version before 3.0 as far as I can tell. Things are fine in 2.9x

Problem: Partly transparent object in shadow glows when HDRI based world lighting is present. With hair cards it is especially noticeable. Test file is not as stark, but issue is still present.

Exact steps for others to reproduce the error

Make a mesh that is partly transparent, where you can see through multiple layers at a time, like a plane with an array modifier so it stacks like a layer cake, enclose it in a box to block all environment light

Give it a partially transparent shader. Ideally an alpha around .1

Position camera inside the box, observing that it is dark inside the box, even if you have a world background lighting the scene

Now set the world background to have an HDRI plugged into the background node. Behold, the mesh glows, but only where you are looking through multiple layers.

It is as if an image world background is illuminating an object when it shouldn’t.

And it only seems to do this when an object has multiple layers of transparency that you are looking through. Turn the array modifier off and it goes dark.

Example image:
image.png

Example of issue in a practical setting. This character's hair does not contain any emissive shader nodes. Loading the same character file in 2.93 without making any changes does not show the "glow".
image.png

Example file:
bug test file.blend

**System Information** Operating system: Windows 10 Graphics card: NVIDIA GeForce RTX 2080 **Blender Version** Broken: 3.0.1, branch: master, date: 2022-01-25 (latest version on blender.org) Worked: Any version before 3.0 as far as I can tell. Things are fine in 2.9x Problem: Partly transparent object in shadow glows when HDRI based world lighting is present. With hair cards it is especially noticeable. Test file is not as stark, but issue is still present. **Exact steps for others to reproduce the error** Make a mesh that is partly transparent, where you can see through multiple layers at a time, like a plane with an array modifier so it stacks like a layer cake, enclose it in a box to block all environment light Give it a partially transparent shader. Ideally an alpha around .1 Position camera inside the box, observing that it is dark inside the box, even if you have a world background lighting the scene Now set the world background to have an HDRI plugged into the background node. Behold, the mesh glows, but only where you are looking through multiple layers. It is as if an image world background is illuminating an object when it shouldn’t. And it only seems to do this when an object has multiple layers of transparency that you are looking through. Turn the array modifier off and it goes dark. - Example image: ![image.png](https://archive.blender.org/developer/F12843007/image.png) - Example of issue in a practical setting. This character's hair does not contain any emissive shader nodes. Loading the same character file in 2.93 without making any changes does not show the "glow". ![image.png](https://archive.blender.org/developer/F12843004/image.png) Example file: [bug test file.blend](https://archive.blender.org/developer/F12843009/bug_test_file.blend)

Added subscriber: @AdrianPreston

Added subscriber: @AdrianPreston

Added subscriber: @iss

Added subscriber: @iss

Changed status from 'Needs Triage' to: 'Needs User Info'

Changed status from 'Needs Triage' to: 'Needs User Info'

Can't reproduce this issue. Does this happen with any HDRI? In provided file none is packed.

Please click on Help > Save System Info and upload saved file.

Can't reproduce this issue. Does this happen with any HDRI? In provided file none is packed. Please click on Help > Save System Info and upload saved file.

Whoops, sorry. I forgot about the HDRI. Yes, it does it with any HDRI that I have tried.
bug test file.blend
I hope I packed that correctly.
Just switching to render preview in the viewport window ought to show it. Here is what it looks like for me.
image.png

Here is the system info file:
system-info.txt

Whoops, sorry. I forgot about the HDRI. Yes, it does it with any HDRI that I have tried. [bug test file.blend](https://archive.blender.org/developer/F12843061/bug_test_file.blend) I hope I packed that correctly. Just switching to render preview in the viewport window ought to show it. Here is what it looks like for me. ![image.png](https://archive.blender.org/developer/F12843062/image.png) Here is the system info file: [system-info.txt](https://archive.blender.org/developer/F12843065/system-info.txt)

One new piece of information: Switching from GPU rendering to CPU rendering makes the problem go away.

One new piece of information: Switching from GPU rendering to CPU rendering makes the problem go away.
Member

Added subscriber: @Alaska

Added subscriber: @Alaska
Member

Changed status from 'Needs User Info' to: 'Confirmed'

Changed status from 'Needs User Info' to: 'Confirmed'
Member

I can confirm the issue when rendering with CUDA with the system information below:

System Information
Operating system: Linux-5.15.0-3-amd64-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03
Blender Version: 3.2.0 Alpha, branch: master, commit date: 2022-02-02 02:53, hash: 9b779993f0

I can confirm the issue when rendering with CUDA with the system information below: **System Information** Operating system: Linux-5.15.0-3-amd64-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03 Blender Version: 3.2.0 Alpha, branch: master, commit date: 2022-02-02 02:53, hash: `9b779993f0`
Member

Upon further investigation the issue affects the CPU if the BVH structure is changed to BVH2. As such it will also affect HIP and Metal?

Upon further investigation the issue affects the CPU if the BVH structure is changed to BVH2. As such it will also affect HIP and Metal?
Alaska changed title from Partly transparent objects appear to glow in the dark when HDRI environment lighting is present to Partly transparent objects appear to glow in the dark when HDRI environment lighting is present (BVH2/Some GPU rendering backends) 2022-02-03 06:33:03 +01:00
Contributor

Added subscriber: @Raimund58

Added subscriber: @Raimund58
Member

@AdrianPreston when investigating a similar report, it was found that increasing the Transparent light bounces property in cycles gets rid of the issue when rendering with an effected rendering backend.
It's not a fix, but it's a work around you, and others, can use if you face this issue with future projects.

@AdrianPreston when investigating a similar report, it was found that increasing the `Transparent light bounces` property in cycles gets rid of the issue when rendering with an effected rendering backend. It's not a fix, but it's a work around you, and others, can use if you face this issue with future projects.

At least in my case increasing the transparent bounces made it dimmer, not totally go away. I suppose I could turn transparent bounces up to something absurd like 100 and see how Blender deals. But this isn't a tech support forum, so I'll work on it on my own and see how good results I can get. Thanks for the workaround.

At least in my case increasing the transparent bounces made it dimmer, not totally go away. I suppose I could turn transparent bounces up to something absurd like 100 and see how Blender deals. But this isn't a tech support forum, so I'll work on it on my own and see how good results I can get. Thanks for the workaround.

This issue was referenced by 04e89c5b06

This issue was referenced by 04e89c5b06739a9a507942e2a9c67fb59b975600

Changed status from 'Confirmed' to: 'Resolved'

Changed status from 'Confirmed' to: 'Resolved'
Sergey Sharybin self-assigned this 2022-03-09 10:39:08 +01:00
Sign in to join this conversation.
No Label
Interest
Alembic
Interest
Animation & Rigging
Interest
Asset Browser
Interest
Asset Browser Project Overview
Interest
Audio
Interest
Automated Testing
Interest
Blender Asset Bundle
Interest
BlendFile
Interest
Collada
Interest
Compatibility
Interest
Compositing
Interest
Core
Interest
Cycles
Interest
Dependency Graph
Interest
Development Management
Interest
EEVEE
Interest
EEVEE & Viewport
Interest
Freestyle
Interest
Geometry Nodes
Interest
Grease Pencil
Interest
ID Management
Interest
Images & Movies
Interest
Import Export
Interest
Line Art
Interest
Masking
Interest
Metal
Interest
Modeling
Interest
Modifiers
Interest
Motion Tracking
Interest
Nodes & Physics
Interest
OpenGL
Interest
Overlay
Interest
Overrides
Interest
Performance
Interest
Physics
Interest
Pipeline, Assets & IO
Interest
Platforms, Builds & Tests
Interest
Python API
Interest
Render & Cycles
Interest
Render Pipeline
Interest
Sculpt, Paint & Texture
Interest
Text Editor
Interest
Translations
Interest
Triaging
Interest
Undo
Interest
USD
Interest
User Interface
Interest
UV Editing
Interest
VFX & Video
Interest
Video Sequencer
Interest
Virtual Reality
Interest
Vulkan
Interest
Wayland
Interest
Workbench
Interest: X11
Legacy
Blender 2.8 Project
Legacy
Milestone 1: Basic, Local Asset Browser
Legacy
OpenGL Error
Meta
Good First Issue
Meta
Papercut
Meta
Retrospective
Meta
Security
Module
Animation & Rigging
Module
Core
Module
Development Management
Module
EEVEE & Viewport
Module
Grease Pencil
Module
Modeling
Module
Nodes & Physics
Module
Pipeline, Assets & IO
Module
Platforms, Builds & Tests
Module
Python API
Module
Render & Cycles
Module
Sculpt, Paint & Texture
Module
Triaging
Module
User Interface
Module
VFX & Video
Platform
FreeBSD
Platform
Linux
Platform
macOS
Platform
Windows
Priority
High
Priority
Low
Priority
Normal
Priority
Unbreak Now!
Status
Archived
Status
Confirmed
Status
Duplicate
Status
Needs Info from Developers
Status
Needs Information from User
Status
Needs Triage
Status
Resolved
Type
Bug
Type
Design
Type
Known Issue
Type
Patch
Type
Report
Type
To Do
No Milestone
No project
No Assignees
6 Participants
Notifications
Due Date
The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: blender/blender#95462
No description provided.