Motion blur cloner objects jittering and flickering

[daniel2SH2D]

Hi there

Having discovered that Arnold scatter doesn't really work for moving or deformed meshes in 'surface' mode, Im using a C4D Object cloner to clone objects onto a moving mesh. I should mention that I'm using GSG 'GorillaCam' with an Arnold tag  for the camera...and that I have baked the MoGraph, and set the Motion Blur to not re-calculate on each frame, because of the bake.

I can't seem to get a 'stable' result, the moving motion blur objects are sort of like AI 'hallucinations' or some such...It's particularly pronounced when set to 'end on frame', with a bit of an improvement on 'center on frame', and I'll run a test with 'start on frame' in about 20 mins...

Output is being Denoised (Optix), and sampling is set to Adaptive, 4-15 AA samples...

Is it maybe the DeNoiser??
When using cloners in C4D should both the objects inside the cloner AND the cloner itself have an Arnold tag, or just one or the other? Do all the settings need to match if both, or will the cloner tag override the individual object tags? 🤔

Many  thanks!

Can get a quick video uploaded, or test scene if that might help...

[daniel2SH2D]

I'm reviewing the frames, and I've tried all the 'frame' options inside the Motion Blur menu, so it's not that.

It looks like the cloner is *cycling through* the clone objects in the cloner, and changing on every other frame... :confused:

Possibly nothing to do with Motion Blur, I tried a render with Deformation set to 'Off', and it removed all the Motion Blur, but the issue remained (and was clearer).

Just crashed trying to preview MoBlur in the IPR, so I've lost all the trials 🤣

I'll do a couple fresh renders and upload some pics

[daniel2SH2D]

OK, so check out these screenshots I've quickly cobbled together from frame 90-95, both without MoBlur and then with...

Look at frame 94 - the **** cactus changes into a totally different model?!?!

Any clues? Cloner is set to Render Instance.

Many thanks!

[daniel2SH2D]

Note you can also see it top right in frame 91, but less obvious than the one in frame 94...

Like I mentioned, run as a sequence the model changes every other frame and gives that AI-video 'hallucination' effect...definitely not what I'm after 🙂

[daniel2SH2D]

Forgot to mention, I'm not up to date with latest version yet...perhaps I should upgrade 🤣

[daniel2SH2D]

OK. so I'm still using C4D R23, and have just tested with Arnold 4.4.0 (more recent than I was using previously).

Same issue...the model changes with MoBlur active.
Gonna try actual instances not render instances.

[daniel2SH2D]

OKAAAAY!!!!

Full cloner instances doesn't have this issue, it's render instances that is the villain here...
Ooh, let me try Multi-Instance, that was crashing the GPU, but might work on CPU...

Nope, Multi-Instance crashes the plugin.

RIGHT THEN.

Heavy Scene, but if that's the way it is, that's the way it is.
Adds about 5s per frame at this horrendous resolution, so maybe an extra 3m per frame at full HD.

😱

I'll attach a stripped file for devs if interested. Or is this a known limitation of cloners and mo-blur?

Ah - I can't attach .c4d files?

[lee_griggs]

>Ah - I can't attach .c4d files?

Try zipping it first.

[daniel2SH2D]

Hi Lee

A simple scene attached >>

Rendering from frame 69-79 demonstrates what was happening.

Thanks

[daniel2SH2D]

Hi again!

Today I've checked a few frames with the cloner fixed to actual instances, and can still report that the geometry of the instances is not at all stable. If you check the cactus in the scene with 3 'arms', it's all over the place in the mo-blur renders, see attached pic, one of the 'arms' isn't there, then it is, then it isn't, then it is again, and then it isn't...

I think I'll have to go back to drawing board here, as I'm 3 days in and chasing my own tail!

[daniel2SH2D]

OK, SORRY for the epic thread! 🤣

It's the effectors that are working on 'visibility' and scaling of the clones...

Not sure why - the falloff should be cool I think - but if I disable them, I get an expected result, and it's something I can jig in the scene to not need the effectors, with a bit of work (probably less work than trying to find out why it's borked!)

The baking of the mograph really hid that influence for the last couple o' days! 😬

Anyway, ALLELUIA!

Arnold is working fine, I think, it's either C4D or my dodgy falloff settings 🤣

As you were!

[daniel2SH2D]

Yeah, this is SOLVED.

It was a wayward effector for the cloner which wasn't properly configured, and although it made no difference in the view-port, made a spooky-ass difference to the render 👻

Entirely my bad, I'll go sit in the corner and think about what I've done.

[peter_horvath]

I'm glad you have found the guilty party (and it's not Arnold 😉).