Arnold 7.1.3.0 new error with gpu rendering

[fuzzlesnuz]

I just starting testing with MtoA 5.2.0 and found out that it now refuses to do any GPU rendering when an R470 driver is installed. Upon starting any render, it will fail within a tenth of a second or so with the following error: "[gpu] NVIDIA driver 47x.xx is too old, version 496.13 or higher is required (GPU-rendering)". MtoA 5.1.3.3 does not have this issue, and will dutifully do GPU rendering on an R470 driver.

There are conflicting messages on what drivers are supported for GPU rendering

• Since Arnold 7.1.0.0, the individual release notes pages for each release specify that the 511.09 drivers are recommended
• However, the Getting Started with Arnold GPU page continues to state that the 472.12 drivers are recommended
• And, of course, the error message in 7.1.3.0's ai.dll itself claims that 496.13 is now a minimum requirement

Note that recommend ≠ required, which is evident by the fact that Arnold 7.1.2.2 and lower will attempt and succeed* at GPU rendering on R470 drivers. The new error message and bail out in Arnold 7.1.3.0 is puzzling, since the 7.1.3.0 release notes do not indicate the presence of any substantial new feature that requires an R495 or R510 driver.

The elephant in the room, Optix 7.4

Arnold 7.1.0.0's change to OptiX 7.4 prompted the 511.09 driver recommendations in the various Arnold literature. (To note: the optix imager since 7.1.0.0 works* just fine on 496.13 as well, so I presume the Arnold team simply only tested on the R510 branch). On an R470 driver, starting a render with an optix imager would immediately fail with the error: "[gpu] NVIDIA driver 47x.xx does not support NVIDIA OptiX 7.4, please use driver version 495". There is a straightforward way to get OptiX 7.4 working on R470 drivers, but the point here is that, while the new 7.4 optix denoiser does require the R495 driver, optix is optional and separate from GPU rendering, which empirically* does not require the R495 driver.

In comparison to Arnold 7.1.0.0's change to OptiX 7.4, nothing in the Arnold 7.1.3.0 release notes jumps out at me as being something that absolutely requires the R495 driver. There is no mention of Arnold extending its use of OptiX beyond the denoiser to require OptiX 7.4's rendering features or other components of the R495 driver.

Conclusion

I'd like to know what specifically is causing the new "NVIDIA driver 47x.xx is too old, version 496.13 or higher is required (GPU-rendering)" error message. I also have my fingers crossed that it is a bug of some sort, or a blind driver version check instead of a feature check.

The conflicting info on the Arnold docs could stand to be resolved as well. There are a lot of proofreading errors scattered around the release notes pages in the last year, too. The MtoA 5.2.0 page says "MtoA 5.1.2 works with the following Maya plugins", for example.

Thanks much in advance to anyone with info on this matter.

*per my use of Arnold, which primarily revolves around aiStandardSurface and notably does not include rendering volumes

[thiago.ize]

Thanks for the feedback. We updated the typos. Let us know if we missed any others.

It's true, if you use the right subset of features in the right way, you could get away with older versions of the nvidia driver. However, knowing which features (like optix 7 denoising) and already fixed bugs in the nvidia driver to avoid can be challenging for most users. We believe requiring a newer driver seems like the safest way to ensure Arnold works out of the box for all users.

I'm curious what the use case is for not upgrading the driver? The minimum we require was released almost a year ago.

[fuzzlesnuz]

Hi thiago.ize,

Thanks for the response.

There is great value in the R470 drivers since it is the most recent driver branch to bear the broad OS compatibility that nvidia drivers were once known for. R495+ is less compatible, artificially requiring redstone 4 and only offered by nvidia in the non-standard DCH format. This can be a showstopper for coexisting with other software in the tool chain that is only stable on/unequivocally requires a mature OS.

On a sidenote, it has been apparent in the last couple years that completing GPU rendering is falling lower and lower on Arnold's priority list. Some essentials, such as shadow matte, still are only half-complete and unfit for producton renders. This is unfortunate, but isn't too suprising; I remember Stephen's or Lee's (or whoever it was) post stating that OptiX was the future of Arnold. However, what is surprising, is that the driver requirement for GPU rendering is suddenly increased, despite no improvements to GPU rendering's feature completeness (not OptiX) since Arnold 7.0.0.0 about a year ago (when R470 was current).

Are you able/willing to divulge what specifically triggers the new insufficient driver version message? Simply starting a GPU render with any scene, even one as simple as an empty scene with no renderables in it, will trigger it. From the pov of the end user, I can't tell what is causing this, but it feels like Arnold is aborting before even attempting to render.

[thiago.ize]

Our GPU dev resources are currently on upgrading to Optix 7 for gpu ray tracing. Once that happens (sorry, can't give an ETA) we'll be in a better position for matching more CPU features. Unfortunately, once we do the upgrade there will be absolutely no way to use older GPU drivers.