Redshift Motion Blur Skipping Frames

[CuriousPeter]

Hey all,

I have a cloth animation from Houdini imported into C4D as an alembic. Rendering in Redshift with motion blur on. I have an issue where some frames are being skipped by the MB resulting in a sharp image.

The cloth is definitely in motion and I have checked the velocity values in Houdini and they are showing consistent throughout the animation.

I've also rendered with the motion vectors AOV on and the offending frames (frames with no motion blur) are showing no vectors/black frames on the frames that are having issues.

Has anyone got an idea on how to solve? Delivery for the project is tomorrow...

Cheers!

[CuriousPeter]

Example of motion vectors - https://imgur.com/a/k6ZVYww

[Dr. Sassi]

Hi CuriousPeter,

Thanks for the effort with the image; however, I can't take any information from it other than seeing a black frame. I always would take your word for it.

What I can work with is a project file, preferably reduced to the minimum setup possible to reproduce that problem.
Without that, the typical way is to guess, which takes longer on your side and may lead to nothing. Hence, I asked for a project file, but there was no image or screen capture. Mentoring and supporting artists over two decades has shown to be the better way. I also do not answer from Memory, which is the base for asking questions because everything might have changed since the last update. So that would be another time waster for you. I hope that long story makes sense

But anyway, let's try it:
Ensure the project settings and the Render Settings have the same frame rate as the Alembic has stored. Check that the Frame Step is set to one and that the image will render if Motion blur is shut off. (Just to exclude things)
If I had a file, My first check would be any alfa channel (Puzzlematte, etc.

Any luck?

Please note that I only touch Dropbox, WeTransfer, Adobe, Apple, and Google Clouds for security reasons, with no exceptions. Thanks for understanding.

Perhaps submit a ticket to tech support as well.
https://www.maxon.net/en/support-center

Cheers

[CuriousPeter]

Hey Dr Sassi,

Unfortunately, I need to deliver today so I won't have time to upload and still have time to render the sequence out. Shame but thanks for the willingness to go to that extent of help! Appreciated.

Everything is set correctly. Rendering fine without motion blur and at the correct frame rate. AOVs and passes are all rendering fine. I'm stumped.
I've tried exporting the simulation from Houdini but still get the same results.

If I find a solution, I'll post the results here. For now, I think I'll have to try and make Resolve's motion blur work...
Thanks for your help regardless.

[Dr. Sassi]

Hi CuriousPeter,

Sorry for the stress; it's not fun. Yes, time is what I try to avoid to take from you.
Since you asked, I checked all internal sources (it's Sunday here, so I was a little bit silent), and after that, I was without any report. I even googled it.

FPS in both places, matching the Alembic. Is the motion vector AOV rendering fine for that frame, to see if the Alembic has the correct data to begin with.

Another wild guess, hopefully not a time waster, is if you change the Timing on the Alembic (Time Remapping) just a tiny amount. Does this help?

Redshift Render View> Edit> Clear View Buffer (just in case)

Fingers crossed, you get it done.

My best wishes