Crashing/unexpected results while rendering custom Node-defined volumetric materials #79682

New Issue

Kestrel · 2020-08-10T10:30:01+02:00

Kestrel commented

2020-08-10 10:30:01 +02:00

System Information
Operating system: Linux-5.6.0-2-amd64-x86_64-with-glibc2.29 64 Bits
Graphics card: AMD Radeon (TM) RX 470 Graphics (POLARIS10, DRM 3.36.0, 5.6.0-2-amd64, LLVM 10.0.0) X.Org 4.6 (Core Profile) Mesa 20.0.7

Blender Version
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-08-11 14:14, hash: a3af59f8e3
Worked: Never

Short description of error
When rendering the attached .blend file, Blender frequently crashes or at the very least fails to render properly. It seems to be something to do with the materials I've defined for Evee to use.

Exact steps for others to reproduce the error
#79682.blend

Open file
Render animation

**System Information** Operating system: Linux-5.6.0-2-amd64-x86_64-with-glibc2.29 64 Bits Graphics card: AMD Radeon (TM) RX 470 Graphics (POLARIS10, DRM 3.36.0, 5.6.0-2-amd64, LLVM 10.0.0) X.Org 4.6 (Core Profile) Mesa 20.0.7 **Blender Version** Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-08-11 14:14, hash: `a3af59f8e3` Worked: Never **Short description of error** When rendering the attached .blend file, Blender frequently crashes or at the very least fails to render properly. It seems to be something to do with the materials I've defined for Evee to use. ![rendering-difference.png](https://archive.blender.org/developer/F8765327/rendering-difference.png) **Exact steps for others to reproduce the error** [#79682.blend](https://archive.blender.org/developer/F8776190/T79682.blend) - Open file - Render animation

Kestrel commented

2020-08-10 10:30:01 +02:00

Added subscriber: @ethereal.visage

Evan Wilson commented

2020-08-10 14:58:22 +02:00

Added subscriber: @EAW

Evan Wilson commented

2020-08-10 14:58:22 +02:00

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

Evan Wilson commented

2020-08-10 14:58:22 +02:00

Thank you for the report. I don't experience any crashes when rendering your file using 2.83.4 or 2.91. I tried 4 times using each version.
My results do look different than yours. There isn't any volumetric material in the file as far as I can tell. How are you making the custom materials?
v2.83.4_0001-0024.mp4

Blender Version
Broken: version: 2.83.1, branch: Unknown, commit date: Unknown Unknown, hash: rBUnknown

In my experience, a string of Unknown appears in the version only when using custom builds. Are you able to reproduce the issue with official builds from Blender.org?
The current LTS version is 2.83.4. Please download it from the link below and see if it fixes your issue.
https://www.blender.org/download/
Also please try the latest nightly builds from here:
https://builder.blender.org/download/

Tested using
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 470/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.35

Blender Version
2.83.4 and 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: b522e834ec

Thank you for the report. I don't experience any crashes when rendering your file using 2.83.4 or 2.91. I tried 4 times using each version. My results do look different than yours. There isn't any volumetric material in the file as far as I can tell. How are you making the custom materials? [v2.83.4_0001-0024.mp4](https://archive.blender.org/developer/F8765960/v2.83.4_0001-0024.mp4) >Blender Version >Broken: version: 2.83.1, branch: Unknown, commit date: Unknown Unknown, hash: rBUnknown In my experience, a string of `Unknown` appears in the version only when using custom builds. Are you able to reproduce the issue with official builds from Blender.org? The current LTS version is 2.83.4. Please download it from the link below and see if it fixes your issue. https://www.blender.org/download/ Also please try the latest nightly builds from here: https://builder.blender.org/download/ --- Tested using Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 470/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.35 **Blender Version** 2.83.4 and 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: `b522e834ec`

Kestrel commented

2020-08-10 20:16:09 +02:00

My apologies, I attached the wrong .blend file... here's the one I meant to upload: athena-animated-2.blend

that's what I get for trying to get in the bug report before I go to sleep :-)

I just tried with the latest Beta blender build (version: 2.90.0 Beta, branch: master, commit date: 2020-08-09 12:07, hash: 00162e6b7b0f, type: Release) and the latest Blender Alpha build (version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: b522e834ec30, type: Release). The Beta build has the same results as the 2.83.1 from the Debian repositories, but progress with the Alpha build! It simply never renders the volumetric effects around the eyes, and also appears to not crash despite repeated runs.

I'll play around with the alpha build to see if I can figure out what I need to tweak to get it working there, and then try those changes in the earlier builds to see if that also fixes things.

My apologies, I attached the wrong .blend file... here's the one I *meant* to upload: [athena-animated-2.blend](https://archive.blender.org/developer/F8766784/athena-animated-2.blend) that's what I get for trying to get in the bug report before I go to sleep :-) I just tried with the latest Beta blender build (`version: 2.90.0 Beta, branch: master, commit date: 2020-08-09 12:07, hash: 00162e6b7b0f, type: Release`) and the latest Blender Alpha build (`version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: b522e834ec30, type: Release`). The Beta build has the same results as the 2.83.1 from the Debian repositories, but progress with the Alpha build! It simply never renders the volumetric effects around the eyes, and also appears to not crash despite repeated runs. I'll play around with the alpha build to see if I can figure out what I need to tweak to get it working there, and then try those changes in the earlier builds to see if that also fixes things.

Kestrel commented

2020-08-10 20:36:54 +02:00

Changing to not use both surface and volumetric rendering for the same NURBS sphere (which ... makes a lot of sense, I'm now unsure how it was working before?) and to instead put a second 'shell' around the eyes that has the volumetric part of the shader and keeping the surface part of the shader on the original sphere. Everything seems stable / as expected in the alpha version of Blender, but it's still crashing in 2.83.1 and has even worse results in the beta version --- whereas before about one frame in fifty had the rendering difference, now about one frame in five does. I've attached the new .blend I've been using to test this.

nightly_test.blend

Changing to **not** use both surface and volumetric rendering for the same NURBS sphere (which ... makes a lot of sense, I'm now unsure how it was working before?) and to instead put a second 'shell' around the eyes that has the volumetric part of the shader and keeping the surface part of the shader on the original sphere. Everything seems stable / as expected in the alpha version of Blender, but it's still crashing in 2.83.1 and has even *worse* results in the beta version --- whereas before about one frame in fifty had the rendering difference, now about one frame in five does. I've attached the new .blend I've been using to test this. [nightly_test.blend](https://archive.blender.org/developer/F8766834/nightly_test.blend)

Evan Wilson commented

2020-08-11 05:21:39 +02:00

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

Richard Antalik commented

2020-08-11 12:57:40 +02:00

Added subscriber: @iss

Richard Antalik commented

2020-08-11 12:57:40 +02:00

Please create one report per issue.

Can not reproduce crash either.

I am unsure what the issue with shading is. Please describe what the issue is in short sentence, make example file as simple as possible by removing unrelated objects and provide exact steps how to perform a test.

Please create one report per issue. Can not reproduce crash either. I am unsure what the issue with shading is. Please describe what the issue is in short sentence, make example file as simple as possible by removing unrelated objects and provide exact steps how to perform a test.

Richard Antalik commented

2020-08-11 12:57:49 +02:00

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

Kestrel commented

2020-08-12 00:11:14 +02:00

Simpler version of the .blend attached. There are two spheres, one strictly inside the other. The outer one is using transparent volumetric shading to produce a "glow" effect, while the inner sphere is rendered using a simple surface shader. The volumetric shading "glow" effect does not always render, leaving only the inner sphere being directly visible. This result is nondeterministic and seems to appear more frequently in earlier versions of Blender, and (let's say unrelatedly for the purposes of this bug report) appears to be highly correlated with a Blender crash. Contrary to what I stated above, I have been able to reproduce this in the Alpha.

I have tested this with three Blender versions so far.

version: 2.83.1 (from the Debian repositories)
version: 2.90.0 Beta, branch: master, commit date: 2020-08-09 12:07, hash: 00162e6b7b, type: Release

version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: `b522e834ec`, type: Release

All three produce frames without the volumetric effect, looking like the sphere on the right side of the below image, while the left is what 90-odd percent of the frames look like (and is the intended / expected look). There does not appear to be any noticeable distribution on which frames the discrepancy appears, from a casual analysis; as far as I can the unexpected results are uniformly distributed across frames.

And here is the .blend:

difference_example.blend

Simpler version of the .blend attached. There are two spheres, one strictly inside the other. The outer one is using transparent volumetric shading to produce a "glow" effect, while the inner sphere is rendered using a simple surface shader. The volumetric shading "glow" effect does not always render, leaving only the inner sphere being directly visible. This result is nondeterministic and seems to appear more frequently in earlier versions of Blender, and (let's say unrelatedly for the purposes of this bug report) appears to be highly correlated with a Blender crash. Contrary to what I stated above, I have been able to reproduce this in the Alpha. I have tested this with three Blender versions so far. - version: 2.83.1 (from the Debian repositories) - version: 2.90.0 Beta, branch: master, commit date: 2020-08-09 12:07, hash: 00162e6b7b0f, type: Release # version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: b522e834ec30, type: Release All three produce frames without the volumetric effect, looking like the sphere on the right side of the below image, while the left is what 90-odd percent of the frames look like (and is the intended / expected look). There does not appear to be any noticeable distribution on which frames the discrepancy appears, from a casual analysis; as far as I can the unexpected results are uniformly distributed across frames. ![expected_and_unexpected.png](https://archive.blender.org/developer/F8770779/expected_and_unexpected.png) And here is the .blend: [difference_example.blend](https://archive.blender.org/developer/F8770789/difference_example.blend)

Kestrel commented

2020-08-13 02:03:06 +02:00

The issue only appears with the Eevee renderer, Cycles is fine. This leads me to suspect my OpenGL implementation, but trying with the Blender 2.91.0 Alpha on Windows x64 with the same .blend file on the same machine gives the same inconsistent results (and crashes). Trying back on Linux with blender-softwaregl also produces the same results.

In case it's relevant, I have an AMD CPU (first-gen Ryzen 1600) and an AMD GPU (Polaris 10 RX 470) in this machine. I'll see if I can get access to a machine with an Intel CPU / Intel or NVidia GPU to see if it might be an AMD-specific problem.

Also, I'm trying to get a debug build of Blender working on Linux to see if I can get a proper backtrace with a recent version of Blender in case something in the crash might be helpful for isolating any problems, will update if/once I get that working.

The issue only appears with the Eevee renderer, Cycles is fine. This leads me to suspect my OpenGL implementation, but trying with the Blender 2.91.0 Alpha on Windows x64 with the same .blend file on the same machine gives the same inconsistent results (and crashes). Trying back on Linux with `blender-softwaregl` also produces the same results. In case it's relevant, I have an AMD CPU (first-gen Ryzen 1600) and an AMD GPU (Polaris 10 RX 470) in this machine. I'll see if I can get access to a machine with an Intel CPU / Intel or NVidia GPU to see if it might be an AMD-specific problem. Also, I'm trying to get a debug build of Blender working on Linux to see if I can get a proper backtrace with a recent version of Blender in case something in the crash might be helpful for isolating any problems, will update if/once I get that working.

Richard Antalik commented

2020-08-13 10:52:57 +02:00

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

Richard Antalik commented

2020-08-13 10:57:34 +02:00

I simplified file a bit more, I was able to reproduce shading error, but I wasn't able to reproduce crash.

Philipp Oeser removed the

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Crashing/unexpected results while rendering custom Node-defined volumetric materials #79682

version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: b522e834ec, type: Release

version: 2.91.0 Alpha, branch: master, commit date: 2020-08-09 00:04, hash: `b522e834ec`, type: Release