Motion blur create wierd artifacts on certain frames when renderring animation with cycles #97571

New Issue

NXSK · 2022-04-23T17:25:50+02:00

NXSK commented

2022-04-23 17:25:50 +02:00

System Information
Operating system: win10
Graphics card: RTX 3090

Blender Version
Broken: 3.1.2 stable

Enabling motion blur may sometimes cause black artifacts on certain frames when renderring animation with cycles.

Exact steps for others to reproduce the error
Don't know how it happens, I uploaded the project file. I found the 12th, 28th frame have the problem mentioned above.

Inherit 2.blend

**System Information** Operating system: win10 Graphics card: RTX 3090 **Blender Version** Broken: 3.1.2 stable Enabling motion blur may sometimes cause black artifacts on certain frames when renderring animation with cycles. ![motion blur issue.jpg](https://archive.blender.org/developer/F13018942/motion_blur_issue.jpg) **Exact steps for others to reproduce the error** Don't know how it happens, I uploaded the project file. I found the 12th, 28th frame have the problem mentioned above. [Inherit 2.blend](https://archive.blender.org/developer/F13018947/Inherit_2.blend)

NXSK commented

2022-04-23 17:25:50 +02:00

Added subscriber: @NXSK

Pratik Borhade commented

2022-04-25 08:12:19 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-04-25 08:30:44 +02:00

Added subscriber: @lichtwerk

Pratik Borhade commented

2022-04-25 08:30:44 +02:00

I can confirm. This has came between 52be063012 - d3b1cce400

@lichtwerk hi, can you help finding the responsible commit?

I can confirm. This has came between 52be06301257 - d3b1cce4000b @lichtwerk hi, can you help finding the responsible commit?

Philipp Oeser commented

2022-04-25 08:51:49 +02:00

In #97571#1346054, @PratikPB2123 wrote:
I can confirm. This has came between 52be063012 - d3b1cce400

@lichtwerk hi, can you help finding the responsible commit?

Are you sure this worked prior to 52be063012?
I can also see this in abf30007ab (when I turn OFF GPU subdiv -- this wasnt working in cycles at that point iirc)
Unsudivided, the error also seems to go away in master

> In #97571#1346054, @PratikPB2123 wrote: > I can confirm. This has came between 52be06301257 - d3b1cce4000b > > @lichtwerk hi, can you help finding the responsible commit? Are you sure this worked prior to 52be063012? I can also see this in abf30007ab (when I turn OFF GPU subdiv -- this wasnt working in cycles at that point iirc) Unsudivided, the error also seems to go away in master

Philipp Oeser commented

2022-04-25 08:55:56 +02:00

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

Philipp Oeser commented

2022-04-25 08:55:56 +02:00

Can confirm the issue though (just dont think it is a recent regression, this might also have to do with the Bevel modifier? Leaving that out also improves the situation)

Brecht Van Lommel commented

2022-05-04 20:55:40 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2022-05-04 20:55:40 +02:00

Changed status from 'Confirmed' to: 'Archived'

Brecht Van Lommel closed this issue

2022-05-04 20:55:40 +02:00

Brecht Van Lommel commented

2022-05-04 20:55:40 +02:00

Motion blur requires either a fixed mesh topology, or a velocity attribute.
https://docs.blender.org/manual/en/latest/render/cycles/object_settings/object_data.html#motion-blur

This geometry node setup has topology changing over time and will not get correct motion blur. On other frames motion blur for this object gets automatically disabled since the number of vertices is different, which can be done manually for objects without a fixed mesh topology.

Motion blur requires either a fixed mesh topology, or a `velocity` attribute. https://docs.blender.org/manual/en/latest/render/cycles/object_settings/object_data.html#motion-blur This geometry node setup has topology changing over time and will not get correct motion blur. On other frames motion blur for this object gets automatically disabled since the number of vertices is different, which can be done manually for objects without a fixed mesh topology.

Brecht Van Lommel commented

2022-05-04 20:57:04 +02:00

It's the geometry nodes that lead to the changing topology by the way, bevel and subsurf are not changing it here as far as I can tell.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Motion blur create wierd artifacts on certain frames when renderring animation with cycles #97571