Weird black splotches and blurred areas

[Rick Eloy]

So, just installed the latest build on a new machine (2x 2070 Super with the latest drivers) and somthing really odd is happening... The viewport preview looks fine, but when I hit render it comes out with a very strange black splotch, kind of like when film is being burned... Also, some areas look blurred (even without motion blur or dof).
Any thoughts on what might be causing this?

[Alexander.Atanasov]

Hi Rick,

This looks like the issue from this thread https://forums.chaosgroup.com/forum/...endered-images. Can you send us an EXR file so we can have a look at the render passes? If that doesn't provide enough information can you send us the scene ? You can send it via this form https://support.chaos.com/hc/en-us and you click on Submit a request in the top-right corner.

Best regards,
Alexander

[npg]

Does it happen if you render the same with a single GPU (Edit->Render Devices)?

[npg]

We have identified the problem and we have implemented a fix. The issue occurs when using multiple GPUs, so until a new build is available, you can avoid it by disabling the second GPU from Edit->Render Devices (if you're using NVLink you will have to disable the link first).

[Rick Eloy]

Well, that's unfortunate... I was really hoping to use both GPUs with Vantage, for we usually have some pretty memory intense scenes... Will have to wait until the next release is up, then.
Tks, everybody!

[Rick Eloy]

Silly question: after disabling one of the GPUs it worked, but now I can't turn that same GPU back on?

[Alexander.Atanasov]

Hi Rick,

Did you disable the GPU from the Render devices dialog or from somewhere else? Maybe something happened when you turned off the NVLink connection.

Best regards,
Alexander

[npg]

Also could you share the file C:\Users\<username>\AppData\Roaming\Chaos Group\Vantage\debug_log.txt - it contains some info about devices the app sees on the machine

[Rick Eloy]

Apparently there was an issue with the NVIDIA driver on the second GPU (appears corrupt, if that's even possible). Our IT team is taking a look right now...

[vishwanath_mani]

So, just installed the latest build on a new machine (2x 2070 Super with the latest drivers) and somthing really odd is happening... The viewport preview looks fine, but when I hit render it comes out with a very strange black splotch, kind of like when film is being burned... Also, some areas look blurred (even without motion blur or dof).
Any thoughts on what might be causing this?

This problem is still in render scenes when you render a Stereo image with high res like 4000x4000.
disabling denoise solves this issue, you can use 2x GPU then. but then you cannot use the saved .exr to denoise it in denoise tool. saving as .png has lot of noise.
We cannot render a Stereo walkthrough with this splotches at all.
Any alternatives.? Thanks
Also enabling Mblur has its problems of blurring the render. So denoise and Mblur cant be used

Can there be an update in coming days ?

[npg]

There was an issue with resolutions larger than 5000x3328 (16640000 pixels) with older NVidia drivers. See here: https://forums.chaos.com/forum/chaos...-renders-error
It should be fixed with new drivers. Are you on the latest drivers? Are you having a different issue at this kind of resolution?

The kind of black splotches we see in the original post happen when the denoiser receives invalid data - it was a bug specific to multi-GPU and it is fixed in 1.5.0. Such black spots also sometimes occur if you're moving the camera through a wall. Disabling "Reduce flickering" may help.

[vishwanath_mani]

There was an issue with resolutions larger than 5000x3328 (16640000 pixels) with older NVidia drivers. See here: https://forums.chaos.com/forum/chaos...-renders-error
It should be fixed with new drivers. Are you on the latest drivers? Are you having a different issue at this kind of resolution?

The kind of black splotches we see in the original post happen when the denoiser receives invalid data - it was a bug specific to multi-GPU and it is fixed in 1.5.0. Such black spots also sometimes occur if you're moving the camera through a wall. Disabling "Reduce flickering" may help.

can we switch "Reduce flickering" off in final render sequence ?

[vishwanath_mani]

There was an issue with resolutions larger than 5000x3328 (16640000 pixels) with older NVidia drivers. See here: https://forums.chaos.com/forum/chaos...-renders-error
It should be fixed with new drivers. Are you on the latest drivers? Are you having a different issue at this kind of resolution?

The kind of black splotches we see in the original post happen when the denoiser receives invalid data - it was a bug specific to multi-GPU and it is fixed in 1.5.0. Such black spots also sometimes occur if you're moving the camera through a wall. Disabling "Reduce flickering" may help.

We are using ltest game ready drivers. yes at 4000x4000 we getting the splotches.

Tested a few frames with "Reduce flickering" off and it did work, only first frame had an issue, rest were clean. on 2x GPPU

[npg]

Unchecking "Reduce flickering" disables the temporal stabilization of the denoiser. So the denoiser will not consider the previous frame when denoising the current frame. If this was leading to artifacts, there was probably some discontinuity between the frames. Was the camera moving through walls/objects or something like that? Or was it jumping to a new location?