Regression: when the scene has multiple volumes, some of them get wrong transformation in Eevee's render #101402

New Issue

System Information
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 516.94

Blender Version
Broken: version: 3.2.0, caused by fa3bd17ae8
Worked: (3.1.2)

Short description of error
When rendering a scene in eevee, that contains volumetric materials applied to volume objects, the rendered result doesn't match the viewport preview. Some volumes are missing and the lighting is wrong. There are also strange rectangular voxel streaks. The issue is also present in Blender 3.2 and 3.4 alpha. It works fine in Blender 3.1.

I'm attaching a file where this error is present.

I've created a few "smoke streaks" by making some simple mesh geometry using the skin modifier and subdivision, then using a mesh to volume and a couple of volume displace modifiers. I've then applied a material with a principled volume shader to the volumes and added some point lights to the scene.

When previewing the scene in the viewport with Eevee, everything looks as desired. But when rendering the scene (using F12), also using Eevee as the renderer, the final rendered image does not coincide with the preview in the viewport. I expect some slight differences between the preview and the final render, but in this case the two results look drastically different and the final render looks wrong and has some visible voxel streak artifacts.

The issue is also present in Blender 3.2.2 and 3.4.0 alpha. However, this exact same scene renders just as previewed in Blender 3.1.2.

For example, this is what the scene looks like in the viewport, and also rendered in Blender 3.1.2, where the issue isn't present:

And this is what it looks like when rendered in Blender 3.3.1 (and also in 3.2.2 and 3.4.0 alpha):

Exact steps for others to reproduce the error

Open attached eevee_volumetric_render_bug-3_2.blend file
press {key F12} to render
Compare viewport result with Render result

Simplified file:
eevee_volumetric_render_bug-3_2.blend

Original file:
blender 3.2+ eevee volumetric render bug 001.blend

Thank you for your time and development!

**System Information** Operating system: Windows-10-10.0.19044-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 516.94 **Blender Version** Broken: version: 3.2.0, caused by fa3bd17ae8 Worked: (3.1.2) **Short description of error** When rendering a scene in eevee, that contains volumetric materials applied to volume objects, the rendered result doesn't match the viewport preview. Some volumes are missing and the lighting is wrong. There are also strange rectangular voxel streaks. The issue is also present in Blender 3.2 and 3.4 alpha. It works fine in Blender 3.1. I'm attaching a file where this error is present. I've created a few "smoke streaks" by making some simple mesh geometry using the skin modifier and subdivision, then using a mesh to volume and a couple of volume displace modifiers. I've then applied a material with a principled volume shader to the volumes and added some point lights to the scene. When previewing the scene in the viewport with Eevee, everything looks as desired. But when rendering the scene (using F12), also using Eevee as the renderer, the final rendered image does not coincide with the preview in the viewport. I expect some slight differences between the preview and the final render, but in this case the two results look drastically different and the final render looks wrong and has some visible voxel streak artifacts. The issue is also present in Blender 3.2.2 and 3.4.0 alpha. However, this exact same scene renders just as previewed in Blender 3.1.2. For example, this is what the scene looks like in the viewport, and also rendered in Blender 3.1.2, where the issue isn't present: ![eevee volumetrics render - blender 3-1-2.jpg](https://archive.blender.org/developer/F13580918/eevee_volumetrics_render_-_blender_3-1-2.jpg) And this is what it looks like when rendered in Blender 3.3.1 (and also in 3.2.2 and 3.4.0 alpha): ![eevee volumetrics render - blender 3-3-1.jpg](https://archive.blender.org/developer/F13580945/eevee_volumetrics_render_-_blender_3-3-1.jpg) **Exact steps for others to reproduce the error** - Open attached `eevee_volumetric_render_bug-3_2.blend` file - press {key F12} to render Compare viewport result with Render result Simplified file: [eevee_volumetric_render_bug-3_2.blend](https://archive.blender.org/developer/F13582050/eevee_volumetric_render_bug-3_2.blend) Original file: [blender 3.2+ eevee volumetric render bug 001.blend](https://archive.blender.org/developer/F13580972/blender_3.2__eevee_volumetric_render_bug_001.blend) Thank you for your time and development!

Added subscriber: @MariusEugenMihai

#101941 was marked as duplicate of this issue

#101620 was marked as duplicate of this issue

Added subscriber: @OmarEmaraDev

I can confirm the difference. But it runs a bit too slow for me to debug this, so I will leave that to someone else.
It appears to me that some of the objects that are disabled in render also have their volume objects disabled in render.

I can confirm the difference. But it runs a bit too slow for me to debug this, so I will leave that to someone else. It appears to me that some of the objects that are disabled in render also have their volume objects disabled in render.

Hi Omar, thank you for the quick reply! The mesh objects used for the mesh to volume modifier of the volume objects are, indeed, hidden from render. But this is desired (as otherwise the mesh objects themselves would also be rendered), and it doesn't affect the final render in Blender 3.1.2, thus behaving as expected. The problem is only in newer versions of Blender.

Added subscriber: @mano-wii

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

I can confirm the problem.
It looks like an old regression.
Here is a simplified file.

eevee_volumetric_render_bug-3_2.blend

(I will bisect at another time)

I can confirm the problem. It looks like an old regression. Here is a simplified file. [eevee_volumetric_render_bug-3_2.blend](https://archive.blender.org/developer/F13582050/eevee_volumetric_render_bug-3_2.blend) (I will bisect at another time)

Added subscriber: @Haddas

Added subscriber: @Rui-huang

Added subscriber: @Jeroen-Bakker

Also happens in viewport rendering. I expect the transform matrices. Also able to reproduce inside the viewport by limiting the number of samples to 1 and switch from workbench to material mode.

Added subscriber: @pragma37

This issue was referenced by f32939af53

This issue was referenced by f32939af53a110365a7563e9a43cba6423f8e94a

This issue was referenced by b918c079da

This issue was referenced by b918c079daf591ce95d0951a6914f9d80c69ffcb

Changed status from 'Confirmed' to: 'Resolved'

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Regression: when the scene has multiple volumes, some of them get wrong transformation in Eevee's render #101402