Arnold in C4D 20 Constantly Freezes

[mgenehoffman]

I don't know what to do here. Arnold, when switching on the IPR, or when clicking a material or any of a number of scenarios, just plain freezes. C4D says it has become unresponsive and I have to kill the task.

Initially I thought it was a licensing error, but I bought a year's license and it seemed to behave for a while, but now I'm back to it being basically unsable.

Windows 10 Pro, latest build

C4D

R20.059

C4DtoA 3.0.1.1

Threadripper 3 3970x

256 Gigs RAM

4x 2080ti

We're supposed to be starting post on a network tv show that we're moving to Arnold for, but this kind of thing makes me wonder if that is really feasible for us or not right now.

Any ideas?

[thiago.ize]

Is this happening for CPU and/or GPU rendering?

[Eden_Soto2]

I'm on a similar rig now and with the CPU, it's extremely stable in C4D... but GPU it's pretty unstable with more than one GPU in the system for me... I experience the same things you've mentioned if I have anything more than one GPU... latest everything (drivers, etc... fresh Windows install... whole nine)

[mgenehoffman]

I am only CPU rendering as I found GPU rendering to be almost completely unusable at this point. Even if I disable or uninstall one of my GPU's so it doesn't crash immediately, it's incredibly unstable and most of my scenes won't even get to render time.

Do I have to remove my GPU's for CPU rendering to be stable?

[mgenehoffman]

I am only CPU rendering as I found GPU rendering to be almost completely unusable at this point. Even if I disable or uninstall one of my GPU's so it doesn't crash immediately, it's incredibly unstable and most of my scenes won't even get to render time.

Do I have to remove my GPU's for CPU rendering to be stable?

[Eden_Soto2]

To answer your question... for me... I can keep all 4 GPUs in and render very stable with the CPU... I still have not been able to render in C4D R21 with the latest Arnold on the GPU unless I physically remove 3 GPUs from the machine... de-selecting 3 GPUs in the Arnold settings in C4D doesn't do it... only physically removing 3 from the system lets me use the GPU, but it's not worth it, because the Threadripper is rendering much faster than just one GPU at a comparable final frame quality

As I've stated in some other threads as well... I can render in Redshift and Octane with all 4 GPUs all day long just fine... so it's not the machine, it's Arnold GPU

[Stephen.Blair]

@ The CPU renderer is completely independent of the GPUs.

The freezes are always with IPR?
Does CINEMA 4D save a _BugReport?

[thiago.ize]

As Eden pointed out, the multi-gpu hangs are a known issue in the currently released Arnold (6.0.1.0). However CPU rendering should be fine. To the right of this page are instructions for how to generate arnold log files in c4dtoa. Could you try writing out a log file with full verbosity and then doing a CPU render? Post the resulting output here, as that might help us to identify at what point it's hanging and maybe even why.

[peter.horvath6V6K3]

Are previous versions similarly unstable, e.g. C4DtoA 3.0.1 or 2.6.2?

[mgenehoffman]

Yes, both CPU and GPU rendering.

[mgenehoffman]

arnold.zip

Here is the log file it created. It froze in IPR, no C4D error or anything, just becomes unresponsive. Hopefully this reveals something.

Also, it says Windows 8 Professional, but it is Win 10 Pro.

[mgenehoffman]

3.0.1 behaved the same way. I have been trying to get 2.6.2 running, but do not have a license file, as I bought an Arnold 6 license and it only lets me authenticate through the Autodesk SSO. Is there a way to get an older license file to try this with 2.6.2?

[thiago.ize]

Thanks. This does confirm you aren't using GPU.

According to the log, it looks like you got a few frames to work before arnold was interrupted at the 25% mark (probably from moving the camera?) and then Arnold says it cleanly finished the partially completed frame. It's not clear from the log if the hang is in c4dtoa or arnold.

I like Peter's suggestion of trying an older version of c4dtoa, as that would help us to figure out if it's a recent regression.

Another diagnostic to try is to keep lowering the number of render threads, possibly until you have just 1, until it works.

[Stephen.Blair]

Just render with a watermark. Arnold is still fully functional, even without a license.

[mgenehoffman]

Same thing occurs with Arnold 5.4.0.2 and C4DtoA 2.6.2.1

Here is the log file for that.

arnold5402.zip

[mgenehoffman]

Tried different thread counts and old version with no luck. It almost always freezes when I click a material to edit the nodes as well. Even if IPR isn't running.

[thiago.ize]

Thanks for reporting this likely isn't due to having a CPU with lots of cores.

[thiago.ize]

OK, I think it's time to get our hands more dirty. Can you supply us with a dump file when c4dtoa is hung? You can do this once c4dtoa is hung, by opening the Task Manager, clicking on "More details", right clicking on the hung c4d app, and selecting "Create dump file".

Then send us that dump file (ideally compressed).

With this we'll be able to see exactly what is the state of c4d, c4dtoa, and arnold when it hung.

[mgenehoffman]

Here it is. I apologize that it's so large.

https://www.dropbox.com/s/1sfljoe9clza4g2/CINEMA%204D.zip?dl=1

[thiago.ize]

This is great, thanks! It looks like this is a legit hang, with both c4dtoa and c4d all waiting for something to happen. It looks like Arnold might have been in the process of being shutdown (essentially all its threads are gone). If this hang happened during IPR, that's very unusual since there should have been plenty of Arnold threads doing work or waiting to do new work for the next frame.

We'll investigate some more on our end.