Strange glitching when motion blur is turned on in 3.5 #106618

New Issue

Adrian Lopez · 2023-04-06T10:46:41+02:00

Adrian Lopez commented

2023-04-06 10:46:41 +02:00

System Information
Operating system: macOS-13.3-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M1 Max 1.2

Blender Version
Broken: version: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: 1be25cfff18b
Worked: (newest version of Blender that worked as expected)

Short description of error
A deforming vehicle renders fine when motion blur is turned off. However when MB is turned on.. strange glitching happens

NOTE.. this only seems to happen when AUTOSMOOTH is turned on

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]

**System Information** Operating system: macOS-13.3-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M1 Max 1.2 **Blender Version** Broken: version: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: `1be25cfff18b` Worked: (newest version of Blender that worked as expected) **Short description of error** A deforming vehicle renders fine when motion blur is turned off. However when MB is turned on.. strange glitching happens NOTE.. this only seems to happen when AUTOSMOOTH is turned on **Exact steps for others to reproduce the error** [Please describe the exact steps needed to reproduce the issue] [Based on the default startup or an attached .blend file (as simple as possible)]

glitch_comparison.mov

8.7 MiB

Adrian Lopez added the

labels 2023-04-06 10:46:42 +02:00

Pratik Borhade commented

2023-04-07 06:05:20 +02:00

Hi, thanks for the report. Might be fixed already: #106394
Please check whether issue persists in 3.6 alpha: https://builder.blender.org/download/daily/

Hi, thanks for the report. Might be fixed already: #106394 Please check whether issue persists in 3.6 alpha: https://builder.blender.org/download/daily/

Pratik Borhade added

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labels 2023-04-07 06:05:38 +02:00

Adrian Lopez commented

2023-04-07 06:23:13 +02:00

Thanks so much for letting me know, Pratik!!! Wonderful news!! it was driving me crazy!

Adrian Lopez closed this issue

2023-04-07 06:23:14 +02:00

Adrian Lopez commented

2023-04-07 06:23:15 +02:00

Thanks so much for letting me know, Pratik!!! Wonderful news!! it was driving me crazy!

Blender Bot added

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labels 2023-04-07 06:23:16 +02:00

Adrian Lopez commented

2023-04-07 07:34:21 +02:00

Pratik,

Unfortunately, it doesnt seem to be fixed in 3.6 alpha. I've attached the scene that breaks... the glitches happen quite frequently during the sequence, frames 11, 17, 19, 32.. all through the sequence. Same glitches on the same frames in 3.5 and 3.6

If you position the playhead on any of these frames - the glitch doesnt appear in the viewport render, but does on a rendered frame.

After several attempts and looking up the issue, setting up custom split normals seemed to stop it, but the object became very faceted. I had to add a weighted normal modifier, with a vertex group smoothing the most egregious faceting.. very frustrating and time consuming

Still grateful that you guys are seeing there is an issue. Strange, when I go on blenderartists - there are posts about this going back to 2.93 - thats a long time for such an obvious bug to survive

let me know if you need any other info

Pratik, Unfortunately, it doesnt seem to be fixed in 3.6 alpha. I've attached the scene that breaks... the glitches happen quite frequently during the sequence, frames 11, 17, 19, 32.. all through the sequence. Same glitches on the same frames in 3.5 and 3.6 If you position the playhead on any of these frames - the glitch doesnt appear in the viewport render, but does on a rendered frame. After several attempts and looking up the issue, setting up custom split normals seemed to stop it, but the object became very faceted. I had to add a weighted normal modifier, with a vertex group smoothing the most egregious faceting.. very frustrating and time consuming Still grateful that you guys are seeing there is an issue. Strange, when I go on blenderartists - there are posts about this going back to 2.93 - thats a long time for such an obvious bug to survive let me know if you need any other info

Pratik Borhade commented

2023-04-07 07:38:37 +02:00

Ok, thanks for the update.

I've attached the scene that breaks

Blend file has not been uploaded. Can you try again?

Ok, thanks for the update. > I've attached the scene that breaks Blend file has not been uploaded. Can you try again?

Pratik Borhade reopened this issue

2023-04-07 07:38:44 +02:00

Blender Bot added

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labels 2023-04-07 07:38:45 +02:00

Pratik Borhade added

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and removed

Status

Needs Triage

labels 2023-04-07 07:38:52 +02:00

Adrian Lopez commented

2023-04-07 07:44:40 +02:00

File wont upload, Pratik.. tried zipping it too... its only 118meg... I could wetransfer it.. but I dont have an email address.

Adrian Lopez commented

2023-04-07 07:48:33 +02:00

Nevermind, found yours in your profile.. sent to you via wetransfer

Pratik Borhade commented

2023-04-07 08:09:48 +02:00

Thanks for the file. I can confirm the artifacts with motion blur + auto smooth.
This is same as #100425, closing.

Thanks for the file. I can confirm the artifacts with motion blur + auto smooth. This is same as #100425, closing.

Pratik Borhade closed this issue

2023-04-07 08:09:49 +02:00

Blender Bot added

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Archived

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labels 2023-04-07 08:09:51 +02:00

Adrian Lopez commented

2023-04-07 08:17:40 +02:00

Pratik, I havent submitted alot of these reports.. what does it mean when you close an issue?

Pratik Borhade commented

2023-04-07 08:21:28 +02:00

In this case, its a duplicate report.
We have an existing report on tracker that describes the same issue.
So I closed this report to keep the discussion under one roof (i.e. #100425).
I'd suggest you to subscribe #100425 for further updates.

In this case, its a duplicate report. We have an existing report on tracker that describes the same issue. So I closed this report to keep the discussion under one roof (i.e. #100425). I'd suggest you to subscribe #100425 for further updates.

Adrian Lopez referenced this issue

2023-04-12 18:53:33 +02:00

Strange shading when motion blur is on (fixed in 3.6, request for backport) #106394

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Strange glitching when motion blur is turned on in 3.5 #106618