Character model disappearing and reappearing for no reason during render

[ssjenforcer191191191]

[c4dtoa] 00:00:01 17393MB WARNING | resetting parameter vlist on /Abra_astronaut/astro_body_tyFlow007Low002 (found: nans or infs)

Degenerate polygon objects found in frame: 2
Degenerate Object: astro_body_tyFlow007Low002

 

This is the only thing in the log that appears.  I have a rigged character with animation applied.

I cannot phathom why this is happening and at random spots in the render, not all the time.

 

 

It was happening at times in the IPR as well, but I couldn't figure out why it was happening.

Sometimes it happens only on one character and then doesn't include the warning

Degenerate polygon objects found in frame: 2
Degenerate Object: astro_body_tyFlow007Low002

[ssjenforcer191191191]

I thought it might have been from the fact I had the air hose geometry applied a soft body tag to it, with a collider tag attached to the astronaut mesh (the geometry that is disappearing).  However, disabling the collider tag doesn't fix the issue.

I tried using a cloth tag with pins animation mix, but although that fixes the issue for my first camera, as soon as the stage changes to my closeup camera, the model disappears entirely for the remainder of the render.

 

 

[ssjenforcer191191191]

Every time I render it seems like the model is invisible for more and more frames.

I tried caching the scene dynamics and it is only visible for one frame.

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Arnold Picture Viewer started at Tue Mar 25 14:06:30 2025
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[c4dtoa] 00:00:01 14976MB WARNING | resetting parameter vlist on /Abra_astronaut/astro_body_tyFlow007Low002 (found: nans or infs)
[c4dtoa] 00:00:04 16803MB WARNING | [disp] /asteroid_highpoly_2: padded bounds could be 70x more efficient. given disp_padding: 0.0170000009, recommended: 8.77305865e-07
Degenerate polygon objects found in frame: 94
Degenerate Object: astro_body_tyFlow007Low002
[c4dtoa] 00:00:00 15113MB WARNING | /tool_case_1_Astronaut/top_low/topfoam_low: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15114MB WARNING | /detonator_cable_sweep|detonator_cable_sweep: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15115MB WARNING | /asteroid_highpoly_1: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15125MB WARNING | /asteroid_highpoly_2: parameter "opaque" is deprecated

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Arnold Picture Viewer started at Tue Mar 25 14:06:51 2025
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[c4dtoa] 00:00:01 15003MB WARNING | resetting parameter vlist on /Abra_astronaut/astro_body_tyFlow007Low002 (found: nans or infs)
[c4dtoa] 00:00:04 16711MB WARNING | [disp] /asteroid_highpoly_2: padded bounds could be 70x more efficient. given disp_padding: 0.0170000009, recommended: 8.77305865e-07
Degenerate polygon objects found in frame: 95
Degenerate Object: astro_body_tyFlow007Low002
[c4dtoa] 00:00:00 15282MB WARNING | /tool_case_1_Astronaut/top_low/topfoam_low: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15283MB WARNING | /detonator_cable_sweep|detonator_cable_sweep: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15283MB WARNING | /asteroid_highpoly_1: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15293MB WARNING | /asteroid_highpoly_2: parameter "opaque" is deprecated

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Arnold Picture Viewer started at Tue Mar 25 14:07:12 2025
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[c4dtoa] 00:00:01 15077MB WARNING | resetting parameter vlist on /Abra_astronaut/astro_body_tyFlow007Low002 (found: nans or infs)
[c4dtoa] 00:00:04 16753MB WARNING | [disp] /asteroid_highpoly_2: padded bounds could be 70x more efficient. given disp_padding: 0.0170000009, recommended: 8.77305865e-07
Degenerate polygon objects found in frame: 96
Degenerate Object: astro_body_tyFlow007Low002
[c4dtoa] 00:00:00 15201MB WARNING | /tool_case_1_Astronaut/top_low/topfoam_low: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15202MB WARNING | /detonator_cable_sweep|detonator_cable_sweep: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15203MB WARNING | /asteroid_highpoly_1: parameter "opaque" is deprecated
[c4dtoa] 00:00:00 15212MB WARNING | /asteroid_highpoly_2: parameter "opaque" is deprecated

[ssjenforcer191191191]

So, apparently the issue might be somehow related to the character model in its entirety that I duplicated for the second smaller character.

I simply rigged and controller constrained the main character and then duplicated the entire thing for the other one.

When I delete the duplicated character, the issue is completely nonexistent.

I will confirm by trying again and see if it holds.

[peter_horvath]

It definitely sounds like an issue with the model, wrong vertices and/or polygons. You can try to enable subdivison to see if that helps.

[ssjenforcer191191191]

Maybe I will have to try that and see.

I just did another IPR and the models both disappeared with that same error for some reason only now again.

However, the picture viewer render is fine still for this one.

[ssjenforcer191191191]

Arnold Tag and Subdivision (linear) has no effect.  Still disappears at random frames.

No rhyme or reason to any of it.

It is possible that when I put the model into accurig to rig it, it messed up the mesh somehow on export.

Even if there is somehow something wrong with the model, why would it simply disappear at random?

[peter_horvath]

Any chance you can send us the model?

[ssjenforcer191191191]

I will when I can.  It was a free model.  I looked at mesh Checker, and many of the polygons showed as grey instead of the majority.  Could that mean something?  

It still happens at random, and not usually the same frames every time I render.

I was using an arnold tag with Subdivision only linear.

I tried applying SDS object with prelinear and then 2 catclark, and i will see if that helps. 

[ssjenforcer191191191]

Here is the rigged model with only the texture maps that make up the astronaut suit body, which is the only geometry that disappears, almost always in the IPR and sometimes randomly in picture viewer.

[ssjenforcer191191191]

If you can't reproduce it somehow, I can also share a scene where it is happening just about every time I use the IPR and usually the first or second frame on one or both characters in the picture viewer.

[ssjenforcer191191191]

I tried upgrading my Arnold from 4.7.8 to see if that would fix it.

When I go to render, it is recompiling every single maketx texture file I had already made before.

Why would it have to do that after upgrading to a newer Arnold version?

Is the newer one different that it requires all older ones to be redone?

I will also see if this new version helps with the VRAM issue where Arnold wasn't dumping all the VRAM it used before and making new renders take extra time to load .

[thiago.ize]

When the texture library used by arnold is upgraded, arnold will by design rebuild the tx files if you have autotx enabled. The reason is that newer versions of the texture library might contain fixes/improvements that will benefit you. And yes, between c4dtoa 4.7.8 and the latest Arnold there was a version of Arnold that had a bug in the texture library that produced totally wrong tx files in certain cases, so this automatic rebuilding of tx files would certainly be appreciated in that case. Unfortunately we don't have logic to track whether a particular old tx file has a bug or would benefit from some new tx optimization, so we have this heavy handed approach. If you were happy with your tx files, disable autotx.

[ssjenforcer191191191]

Thanks.

It also didn't fix my disappearing geometry.  I reverted back to 4.7.8 as it kept generating tx files every time I rendered, which caused my VRAM to cap out and rendering slowed a lot.

[peter_horvath]

Sorry for the delayed reply. I could not reproduce the issue with your model yet. I think I'm going to need your scene as well.

[peter_horvath]

> I reverted back to 4.7.8 as it kept generating tx files every time I rendered, which caused my VRAM to cap out and rendering slowed a lot.

As Thiago said, re-generating Tx files are expected after upgrading. But each file should be generated only once at the first access. Following renders should just use the already generated Tx files. Do you mean that the same textures are being generated over and over again every render?

[ssjenforcer191191191]

It did at least the second time I tried rendering, it started generating the same tx files over again, so I stopped it and reverted back.

[peter_horvath]

That's odd, it sounds like a bug, textures should be generated only once. Unless the color space changes or the texture is modified between the renders, or the first generation failed. I can't reproduce this either though, tx generation behaves properly for me. Maybe it depends on the texture. If you see this behavior again, please report it and send us a scene/texture that we can start investigating with.

[ssjenforcer191191191]

I stopped the first frame just after the tx files were all generated and tried rendering again to see, and it started generating them all again.  Maybe I interrupted the process somehow the first frame?

Either way, here is a link for my scene to test the disappearing astronaut.

https://mega.nz/folder/AEZFhZpA#L2snrqLJtgFoB-FTk4g2uA

I can only provide a couple of relevant models, as my total 3D model files are 17 GB.

The disappearing is random.  Sometimes I render all frames and it doesn't happen, sometimes only a few frames randomly.

I cannot replicate it exactly, however, switching cameras while in IPR can trigger it.

I don't know if the animation effects it or not.  Likely not, as far as I can tell.

The character rigging is not very great, but it happens or doesn't happen on the same frame seemingly randomly.

[ssjenforcer191191191]

As far as I know, the model disappearing is the only one with skin tags and rigging.  Maybe it's not playing nice for some reason?